Electrode units for sensing physiological electrical activity

ABSTRACT

Systems and apparatus for monitoring physiological electrical activity of an individual include a first electrode unit for receiving a first signal indicative of electrical activity at a first location on a body of the individual and a second electrode unit for receiving a second signal indicative of electrical activity at a second location on the body of the individual. Each of the first and second electrode units may be operated in a field-sensing mode wherein the electrode unit is placed on or in proximity to the individual&#39;s skin. The first and second electrode units comprise a capacitive sensor element, and the capacitive sensor element of each of the electrode units comprising an electrodynamic sensor which is sensitive to electromagnetic waves; and an antenna comprising an electrically conductive radiating element for receiving electromagnetic waves. The field-sensing mode can be either non-contact field-sensing mode wherein the electrode unit is placed on the individual&#39;s clothing or a contact field-sensing mode wherein the electrode unit is placed directly on the individual&#39;s skin.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of U.S. patent application Ser. No.14/377,255 which is a 35 U.S.C. §371 national phase entry application ofPatent Cooperation Treaty Application No. PCT/US2013/025432 filed 8 Feb.2013 entitled ECG SYSTEM WITH MULTI MODE ELECTRODE UNITS, which in turnclaims priority from U.S. provisional application No. 61/596,543 filed 8Feb. 2012 entitled REMOTE MONITORING ECG SYSTEM. PCT/US2013/025432 andUS61/596,543 are both hereby incorporated herein by reference.

TECHNICAL FIELD

The technology described herein relates to electrocardiography (ECG)systems, electroencephalography (EEG) systems, electromyography (EMG)systems, electrooculography (EOG) systems and/or similar systems, whichdetect physiological electrical activity at locations on, or within, anindividual's body.

BACKGROUND

A conventional ECG system typically consists of between 3 and 10electrodes placed on areas of an individual's body to detect electricalactivity. The electrodes are connected to an ECG monitor by acommensurate number of wires/cables. A conventional ECG electrodetypically comprises a resistive sensor element which is placed directlyagainst the individual's skin. A number of electrodes are placed againstthe individual's skin to detect the electrical characteristics of theheart (e.g. the current through or voltage across the resistive sensorelement) at desired vantage points on the individual's body. Thedetected signals are relayed through the wires to the ECG monitor, whichis typically located on a lab table or the like, away from theindividual's body. A signal processing unit within the ECG monitorprocesses the signals to generate an ECG waveform which can be displayedon a display of the ECG monitor.

FIGS. 1 and 2 show three electrodes 10, 12, 14 arranged in the so-calledEinthoven's triangle on an individual's body 16. As is known in the art,electrodes 10, 12 and 14 may be respectively referred to as the RightArm (RA), Left Arm (LA) and Left Leg (LL) electrodes because of thelocations that they are commonly placed on body 16. To generate an ECGsignal, various potential differences are determined between the signalsfrom electrodes 10, 12, 14. These potential differences are referred toas “leads”. Leads have polarity and associated directionality. Thecommon leads associated with the Einthoven's triangle shown in FIGS. 1and 2 include: lead I (where the signal from RA electrode 10 issubtracted from the signal from LA electrode 12); lead II (where thesignal from RA electrode 10 is subtracted from the signal from LLelectrode 14); and lead III (where the signal from LA electrode 12 issubtracted from the signal from LL electrode 14). In addition to theleads shown in FIG. 2, other common leads associated with theEinthoven's triangle configuration include: the AVR lead (where one halfof the sum of the signals from LA and LL electrodes 12, 14 is subtractedfrom the signal for RA electrode 10); the AVL lead (where one half ofthe sum of the signals from RA and LL electrodes 10, 14 is subtractedfrom the signal for LA electrode 12); and the AVF lead (where one halfof the sum of the signals from RA and LA electrodes 10, 12 is subtractedfrom the signal for LL electrode 14). As is known in the art, the AVRlead is oriented generally orthogonally to lead III, the AVL lead isoriented generally orthogonally to lead II and the AVF lead is orientedgenerally orthogonally to lead I. The signals from each of these leadscan be used to produce an ECG waveform 18 as shown in FIG. 3. Additionalsensors can be added to provide different leads which may be used toobtain different views of the heart activity. For example, as is wellknown in the art, sensors for precordial leads V1, V2, V3, V4, V5, V6may be added and such precordial leads may be determined to obtain theso-called 12 lead ECG.

Some issues with traditional ECG technology make it an impediment foruse, particularly in emergency response situations. The multipleelectrodes and their corresponding wires may require extensive time toset up which may be critical in emergency circumstances. Having tomaneuver around and detangle a large number of wires can be a nuisance.Multiple electrodes and wires can make it difficult to move anindividual or administer medical aid to an individual. Signal noise frommovement of the wires and wire tension can also degrade the quality ofthe ECG reading. Multiple wires can be particularly problematic duringcardiac monitoring, where the ECG wires are attached to an individualfor a long time. These issues with traditional ECG technology areexacerbated where there is a significant distance between the individualand the ECG monitor (i.e. where the electrode wires are long). EEGsystems (which measure electrical activity of the brain), EMG systems(which measure electrical activity of skeletal and/or other muscles)and/or EOG systems (which measure electrical activity within the eye)may face similar problems.

In addition to the problems with wires, current ECG systems use contactelectrodes with resistive sensor elements. Such contact electrodes mustbe placed in direct contact with the individual's skin to obtainaccurate signals. Typically, these contact electrodes are stuck to theindividual's skin using an adhesive. The use of contact electrodes canbe problematic in some circumstances. By way of non-limiting example, itmay be undesirable or difficult to remove the individual's clothing incertain situations—e.g. where the individual may have privacy concerns,where the individual is suspected of having a spinal cord injury and/orthe like. As another example, the individual may have a condition whichmakes it undesirable or difficult to apply current-sensing electrodes tothe skin—e.g. the individual is suffering from burns to the individual'sskin, the individual has body hair which must be removed prior to usingthe contact electrodes, the individual is allergic to the adhesiveand/or the like. Also, EEG systems often require conductive gels to beused between the sensor and the skin of the individual and/or abrasionof the individual's skin to create electrical contact between the sensorand the skin. It can take a long time (e.g. up to an hour or more) toapply the gel into EEG caps and/or nets that are used in EEG sensingsystems. The gel used in EEG systems can diffuse through hair to createshorts between sensors and can dry out over time. Whether gel-coated ornot, the caps or nets which hold EEG sensors in contact with skin can beuncomfortable for the individual being tested, making long termmonitoring (e.g. a desire when evaluating certain conditions such asepilepsy) difficult.

There is a general desire for improved ECG, EEG, EMG, and/or EOGsystems. By way of non-limiting example, there is a general desire foran ECG system that can provide greater flexibility for use by medicalprofessionals in a variety of different circumstances, such as might bethe case for emergency response technicians (EMTs). There is a generaldesire for ECG, EEG, EMG and/or EOG systems that may be more convenientand/or simple to use than existing systems. There is also a generaldesire for improved systems for detecting electrical activity indifferent locations on and/or within an individual's body, such as theheart (e.g. heart muscle), brain, the eyes, and skeletal and/or othermuscles.

The foregoing examples of the related art and limitations relatedthereto are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification and a study of the drawings.

SUMMARY

One aspect of the invention provides an electrode unit for sensingphysiological electrical activity of an individual. Such an electrodeunit may be used, for example, in an ECG, EEG, EOG, or EMG system. Theelectrode unit comprises a capacitive sensor element for sensingelectrical field associated with the physiological electrical activity.The capacitive sensor element of the electrode unit comprises anelectrodynamic sensor which is sensitive to electromagnetic waves (e.g.electric field) and an antenna comprising an electrically conductiveradiating element for receiving electromagnetic waves. The radiatingelement is in electrical contact with a sensing surface of theelectrodynamic sensor and has a surface area which is larger than asurface area of the sensing surface of the electrodynamic sensor. Theantenna is located relatively more proximate than the electrodynamicsensor to the individual's skin during operation of the electrode unitin the field-sensing mode.

In some embodiments, the electrode unit may operate in current sensing,field-sensing non-contact, or field-sensing contact modes. In otherembodiments, the electrode unit may operate in field-sensing mode only.In some embodiments, the electrode unit is incorporated into theinterior of a vehicle for use with a system for sensing physiologicalelectrical activities in an individual. In some embodiments, theelectrode unit may be embedded or mounted within or incorporated in thebackrest or bottom portion of a seat or chair (e.g., seats (e.g.operator seat(s) and/or other seat(s)) in a vehicle such as a car,plane, helicopter, motorcycle, truck, boat, cart, or the like, carseats, strollers, and/or the like), in the controls of a vehicle (e.g.,in the handle bars of a motorcycle, in the steering wheel of a car,and/or the like), in a bed (e.g. a hospital bed, crib, bed frame, and/orthe like), and/or the like. In some embodiments, the electrode unit maybe embedded in seat restraints, such as a seat belt, safety belt, andthe like.

In some embodiments, at least two of these electrode units, eachcomprising a capacitive sensor element that comprises an electrodynamicsensor and an antenna, are used in a system for sensing physiologicalelectrical activities in an individual, such as an ECG, EMG, EEG, or EOGsystem. In some embodiments, only one such electrode unit is used insuch systems. In some embodiments, a plurality of such electrode unitsis used in such systems. In some embodiments, to the system for sensingphysiological electrical activities is incorporated into or embedded ormounted within a vehicle, such as a car, plane, helicopter, motorcycle,truck, boat, cart, or the like, car seats, strollers, and/or the like.In some embodiments, the vehicle may be a police car, an ambulance, afire engine, and/or the like, or a military vehicle, such as a tank,armored vehicle, infantry vehicle, amphibious vehicle, troop carrier,engineering vehicle, military aircraft and/or the like.

Another aspect of the invention provides a method for sensingphysiological electrical activities of an individual, the methodcomprises the steps of providing a first electrode unit for generating afirst signal indicative of the electrical activity at a first locationon a body of the individual; and providing a second electrode unit forgenerating a second signal indicative of the electrical activity at asecond location on the body of the individual. The electrode units arethen operated in field-sensing mode to generate the first signal and thesecond signal, and the first signal and the second signal are used togenerate waveforms indicative of the electrical activity. In someembodiments, one or more of the electrode units comprises a capacitivesensor element, and the capacitive sensor element comprises anelectrodynamic sensor which is sensitive to electromagnetic waves, andan antenna comprising an electrically conductive radiating element forreceiving electromagnetic waves.

In some embodiments, the method comprises providing a plurality ofelectrode units. In some embodiments, the electrode units operate onlyin field sensing mode. In some embodiments, some electrode units mayoperate in field sensing mode and some electrode units may operate incurrent sensing mode. In some embodiments, electrode units operating infield sensing mode may be in field-sensing contact mode or field-sensingnon-contact mode or either mode depending on the instructions providedto the electrode units. In some embodiments, the physiologicalelectrical activity measured comprises electrical activity of the heartmuscle (ECG), the brain (EEG), skeletal muscles (EMG), or the eye (EOG).

In some embodiments, the method for sensing physiological electricalactivity is used to sense physiological electrical activity of anindividual in a vehicle, such as the vehicle operator, passenger, and/orthe like. In some embodiments, the vehicle comprises a car, plane,helicopter, motorcycle, truck, boat, cart, or the like, emergencyresponder vehicles such as a police car, an ambulance, a fire engine,and/or the like, or a military vehicle, such as a tank, armored vehicle,infantry vehicle, amphibious vehicle, troop carrier, engineeringvehicle, military aircraft and/or the like. In some embodiments, themethod is used to sense physiological electrical activities of babies,infants, or young children in car seats, strollers, and/or the like.

Another aspect of the invention provides a system for monitoring heartmuscle activity of an individual comprising: a first electrode unit forgenerating a first signal indicative of electrical activity of the heartmuscle at a first location on a body of the individual; and a secondelectrode unit for generating a second signal indicative of electricalactivity of the heart muscle at a second location on the body of theindividual. Each of the first and second electrode units is configurableto operate in: a field-sensing mode wherein the electrode unit isconfigured to generate its corresponding signal based on a detectedelectric field at a location on or in proximity to the individual'sskin; and a current-sensing mode wherein the electrode unit isconfigured to generate its corresponding signal based on current flowthrough a resistive sensor element placed directly on the individual'sskin.

Another aspect of the invention provides an electrode unit for use in anECG system comprising: a capacitive sensor element for detectingelectric field; a spring-biased clamp for attachment of the electrodeunit to an individual's clothing when operating in a non-contactfield-sensing mode; and an attachment means for physical and electricalattachment of the electrode unit to a resistive sensor element whenoperating in a resistive mode.

Another aspect of the invention provides a system for monitoring heartmuscle activity of an individual comprising: a first electrode unit forgenerating a first signal indicative of electrical activity of the heartmuscle at a first location on a body of the individual, the firstelectrode unit comprising a first capacitive sensing element fordetecting electric field; a second electrode unit for generating asecond signal indicative of electrical activity of the heart muscle at asecond location on the body of the individual, the second electrode unitcomprising a second capacitive sensing element for detecting electricfield; and a plurality of inputs, each input adapted to receive acorresponding signal from a current-sensing electrode unit indicative ofelectrical activity at a corresponding location on the body of theindividual.

Another aspect of the invention provides a system for monitoring heartmuscle activity of an individual comprising: a first input for receivinga first signal indicative of electrical activity of the heart muscle ata first location on a body of the individual; a second input forreceiving a second signal indicative of electrical activity of the heartmuscle at a second location on the body of the individual; wherein eachof the inputs is adapted to receive a signal from a field-sensingelectrode unit or from a current-sensing electrode unit and the systemis configured to differentiate between signals received fromfield-sensing electrode units and signals received from current-sensingelectrode units and to generate one or more ECG waveforms based on thereceived signals.

Another aspect of the invention provides a system for monitoring heartmuscle activity of an individual comprising: a first field-sensingelectrode unit for generating a first signal indicative of electricalactivity of the heart muscle at a first location on a body of theindividual, the first field-sensing electrode unit configured togenerate the first signal based on a detected electric field at alocation on or in proximity to the individual's skin; and a secondcurrent-sensing electrode unit for generating a second signal indicativeof electrical activity of the heart muscle at a second location on thebody of the individual, the second current-sensing electrode unitconfigured to generate the second signal based on current flow through aresistive sensor element placed directly on the individual's skin;wherein the system is configured to combine the first signal and thesecond signal to generate an ECG waveform.

Another aspect of the invention provides a method for generating a ECGwaveform related to heart muscle activity of an individual, the methodcomprising: providing a plurality of electrode units, each electrodeunit configured to generate a corresponding signal indicative ofelectrical activity of the heart muscle at a corresponding location on abody of the individual; operating at least one first one of theplurality of electrode units in a field-sensing mode, wherein the atleast one first one of the electrode units is configured to generate itscorresponding signal based on a detected electric field at a location onor in proximity to the individual's skin; operating at least one otherone of the plurality of electrode units in a current-sensing mode,wherein the at least one other one of the plurality of electrode unitsis configured to generate its corresponding signal based on current flowthrough a resistive sensor element placed directly on the individual'sskin; and using the signals generated by the at least one first one ofthe plurality of electrode units and generated by the at least one otherone of the plurality of electrode units to generate one or more ECGwaveforms.

Another aspect of the invention provides a system for monitoringphysiological electrical activity of an individual (e.g. of an organ,such as the heart (e.g. the heart muscle), brain, eye, or skeletaland/or other muscle) comprising: a first electrode unit for generating afirst signal indicative of the physiological electrical activity (e.g.electrical activity of the heart muscle, brain, eye, or skeletal and/orother muscle, as applicable) at a first location on a body of theindividual; and a second electrode unit for generating a second signalindicative of physiological electrical activity (e.g. electricalactivity of the heart muscle, brain, eye, or skeletal and/or othermuscle, as applicable) at a second location on the body of theindividual. Each of the first and second electrode units is configurableto operate in: a field-sensing mode wherein the electrode unit isconfigured to generate its corresponding signal based on a detectedelectric field at a location on or in proximity to the individual'sskin; and a current-sensing mode wherein the electrode unit isconfigured to generate its corresponding signal based on current flowthrough a resistive sensor element placed directly on the individual'sskin.

Another aspect of the invention provides an electrode unit for use in asystem for measuring physiological electrical activity (e.g. an ECG,EEG, EMG and/or EOG system) comprising: a capacitive sensor element fordetecting electric field; a spring-biased clamp for attachment of theelectrode unit to an individual's clothing when operating in anon-contact field-sensing mode; and an attachment means for physical andelectrical attachment of the electrode unit to a resistive sensorelement when operating in a resistive mode.

Another aspect of the invention provides a system for monitoringphysiological electrical activity of an individual (e.g. electricalactivity of an organ, such as the heart (e.g. the heart muscle), brain,eye, or skeletal and/or other muscle) comprising: a first electrode unitfor generating a first signal indicative of the physiological electricalactivity (e.g. electrical activity of the heart muscle, brain, eye, orskeletal and/or other muscle, as applicable) at a first location on abody of the individual, the first electrode unit comprising a firstcapacitive sensing element for detecting electric field; a secondelectrode unit for generating a second signal indicative of thephysiological electrical activity (e.g. electrical activity of the heartmuscle, brain, eye, or skeletal and/or other muscle, as applicable) at asecond location on the body of the individual, the second electrode unitcomprising a second capacitive sensing element for detecting electricfield; and a plurality of inputs, each input adapted to receive acorresponding signal from a current-sensing electrode unit indicative ofelectrical activity at a corresponding location on the body of theindividual.

Another aspect of the invention provides a system for monitoringphysiological electrical activity of an individual (e.g. electricalactivity of an organ, such as the heart (e.g. the heart muscle), brain,eye, or skeletal and/or other muscle) comprising: a first input forreceiving a first signal indicative of the physiological electricalactivity of the individual (e.g. electrical activity of the heartmuscle, brain, eye, or skeletal and/or other muscle, as applicable) at afirst location on a body of the individual; a second input for receivinga second signal indicative of the physiological electrical activity ofthe individual (e.g. electrical activity of the heart muscle, brain,eye, or skeletal and/or other muscle, as applicable) at a secondlocation on the body of the individual; wherein each of the inputs isadapted to receive a signal from a field-sensing electrode unit or froma current-sensing electrode unit and the system is configured todifferentiate between signals received from field-sensing electrodeunits and signals received from current-sensing electrode units. Thesystem may generate one or more ECG, EEG, EOG, or EMG waveforms, asapplicable, based on the received signals.

Another aspect of the invention provides a system for monitoring thephysiological electrical activity of an individual (e.g. electricalactivity of an organ, such as the heart (e.g. the heart muscle), brain,eye, or skeletal and/or other muscle) comprising: a first field-sensingelectrode unit for generating a first signal indicative of thephysiological electrical activity (e.g. electrical activity of the heartmuscle, brain, eye, or skeletal and/or other muscle, as applicable) at afirst location on a body of the individual, the first field-sensingelectrode unit configured to generate the first signal based on adetected electric field at a location on or in proximity to theindividual's skin; and a second current-sensing electrode unit forgenerating a second signal indicative of the physiological electricalactivity (e.g. electrical activity of the heart muscle, brain, eye, orskeletal and/or other muscle, as applicable) at a second location on thebody of the individual, the second current-sensing electrode unitconfigured to generate the second signal based on current flow through aresistive sensor element placed directly on the individual's skin. Thesystem may be configured to combine the first signal and the secondsignal to generate an ECG, EEG, EOG, or EMG waveform, as applicable.

Another aspect of the invention provides a method for sensingphysiological electrical activity of an individual (e.g. electricalactivity in the heart (e.g. the heart muscle), brain, eye, or skeletaland/or other muscle of an individual) and, optionally, generating ECG,EEG, EOG, or EMG waveforms related to the physiological electricalactivity. The method comprises: providing a plurality of electrodeunits, each electrode unit configured to generate a corresponding signalindicative of the physiological electrical activity (e.g. electricalactivity of the heart muscle, brain, eye, or skeletal and/or othermuscle, as applicable) at a corresponding location on a body of theindividual; operating at least one first one of the plurality ofelectrode units in a field-sensing mode, wherein the at least one firstone of the electrode units is configured to generate its correspondingsignal based on a detected electric field at a location on, or inproximity to, the individual's skin; operating at least one other one ofthe plurality of electrode units in a current-sensing mode, wherein theat least one other one of the plurality of electrode units is configuredto generate its corresponding signal based on current flow through aresistive sensor element placed directly on the individual's skin. Themethod may comprise using the signals generated by the at least onefirst one of the plurality of electrode units and generated by the atleast one other one of the plurality of electrode units to generate oneor more ECG, EEG, EOG, or EMG waveforms, as applicable

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thedrawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered illustrative rather than restrictive.

FIG. 1 is a schematic illustration of the electrodes of a conventionalECG system arranged on the individual's body in an Einthoven's triangleconfiguration.

FIG. 2 is a schematic illustration of the electrodes of a conventionalECG system arranged in an Einthoven's triangle configuration and anumber of the corresponding leads.

FIG. 3 is a typical ECG waveform of the type that might be displayed onan ECG system.

FIG. 4A schematically illustrates an ECG system architecture accordingto a particular embodiment. FIG. 4B schematically illustrates an ECGsystem architecture according to another particular embodiment. FIG. 4Cschematically illustrates an ECG system architecture according toanother particular embodiment. FIG. 4D schematically illustrates an ECGsystem architecture according to another particular embodiment.

FIG. 5A is a block diagram showing one implementation of a signalprocessing system for processing data from the electrode units of theFIGS. 4A-4D ECG systems according to a particular embodiment. FIG. 5B isa block diagram showing one implementation of a signal processing systemfor processing data from the electrode units of the FIGS. 4A-4D ECGsystems according to another particular embodiment.

FIGS. 6A and 6B are respectively assembled and exploded isometric viewsof a multi-mode electrode unit according to a particular embodiment.

FIGS. 7A and 7B illustrate different resistive sensor elements that maybe used with the FIGS. 6A, 6B electrode unit.

FIG. 8 is an exploded cross-sectional view of a capacitive sensorelement that may be used with the FIG. 6A, 6B electrode unit accordingto a particular embodiment.

FIG. 9 illustrates a harness comprising electrode assemblies accordingto a particular embodiment.

FIG. 10 schematically illustrates an EEG system architecture accordingto a particular embodiment.

FIG. 11 schematically illustrates an EMG system architecture accordingto another particular embodiment.

FIG. 12 schematically illustrates an EOG system architecture accordingto another particular embodiment.

DESCRIPTION

Throughout the following description, specific details are set forth inorder to provide a more thorough understanding to persons skilled in theart. However, well known elements may not have been shown or describedin detail to avoid unnecessarily obscuring the disclosure. Accordingly,the description and drawings are to be regarded in an illustrative,rather than a restrictive, sense.

One aspect of the invention provides an electrode unit for sensingphysiological electrical activity of an individual. Such an electrodeunit may be used, for example, in an ECG, EEG, EOG, or EMG system. Theelectrode unit comprises a capacitive sensor element for sensingelectrical field associated with the physiological electrical activity.In some embodiments, the capacitive sensor element of the electrode unitcomprises an electrodynamic sensor which is sensitive to electromagneticwaves (e.g. electric field) and an antenna comprising an electricallyconductive radiating element for receiving electromagnetic waves. Infurther embodiments, the radiating element is in electrical contact witha sensing surface of the electrodynamic sensor and has a surface areawhich is larger than a surface area of the sensing surface of theelectrodynamic sensor. The antenna may be located relatively moreproximate than the electrodynamic sensor to the individual's skin duringoperation of the electrode unit in the field-sensing mode. In someembodiments, the electrode unit may operate in current sensing,field-sensing non-contact, and field-sensing contact modes. In otherembodiments, the electrode unit may operate in field-sensing mode only.In some embodiments, the electrode unit is incorporated into systems forsensing physiological electrical activities of an individual, such as anECG, EEG, EMG, or EOG system. In some embodiments, the electrode unit isprovided as part of a method for sensing physiological electricalactivities of an individual.

FIG. 4A schematically illustrates an ECG system 100 according to aparticular embodiment. ECG system 100 comprises a base unit 102 and twoor more electrode units 104A, 104B, 104C (collectively and individually,electrode units 104). Electrode units 104 may be located relative to anindividual's body 101 (as discussed in more detail below) to generatesignals indicative of electrical activity of the individual's heart attheir corresponding locations. In the schematic illustration of FIG. 4A,locations 101 on the individual's body are shown as being above thethick dashed line 103 and locations 105 away from the individual's bodyare shown as being below the thick dashed line 103. In currentlypreferred embodiments, electrode units 104 are multi-function electrodeunits of the type described below, although this is not necessary. Inthe illustrated embodiment of FIG. 4A, ECG system 100 is shown as havingthree electrode units 104A, 104B, 104C which may be used in anEinthoven's triangle configuration. In some embodiments, third electrodeunit 104C is not necessary and system 100 may use as few as twoelectrode units 104. In some embodiments, system 100 may be providedwith more than three electrode units 104 (as discussed in more detailbelow) to provide additional leads and corresponding additional views ofheart muscle electrical activity. In some embodiments, discussed in moredetail below, electrode units 104 may additionally or alternatively beused to sense other types of electrically-based physiological phenomena(referred to herein as physiological electrical activity), such as, byway of non-limiting example, electrical activity of the brain (e.g. EEGdata), electrical activity associated with skeletal muscles (e.g. EMGdata), electrical activity of the eye (e.g. EOG data) and/or the like.

In the FIG. 4A embodiment, electrode units 104 are removably connectedto base unit 102 by corresponding cables 106A, 106B, 106C (collectivelyand individually, cables 106) which may be removably connected to baseunit 102 using suitable electrical, signal transmission connectors 108A,108B, 108C (collectively and individually, connectors 108). Connectors108 may comprise, for example: slidable locking electric connectors,spring-biased electric connectors, magnetic connectors and/or the like.Base unit 102 is preferably constructed to be sufficiently small andlightweight that it can comfortably rest on an individual's body 101without discomfort and without impacting the individual's ECG waveform.By way of non-limiting example, base unit 102 could be rested on anindividual's chest, strapped or clipped (using suitable straps (notshown) or clips (not shown)) to the individual's clothing, arm or leg,and/or the like. With base unit 102 being so proximate to theindividual, cables 106 may be correspondingly short. In someembodiments, cables 106 are less than 50 cm in length. In someembodiments, cables 106 are less than 30 cm in length.

In the illustrated embodiment, ECG waveforms 110 generated by ECG system100 are displayed on a display 120. In some embodiments, display 120 maybe integral with base unit 102. However, in the illustrated embodiment,display 120 is removably attached to base unit 102 at cradle 122, sothat display 120 can be separated from base unit 120 to a location 105away from the individual's body to permit easy reading by medicalprofessionals without requiring the medical professionals to lean overtop of or otherwise crowd the individual's body 101. In the illustratedembodiment, ECG waveforms 110 are wirelessly communicated to display 120when display 120 is detached from base unit 102. When display 120 islocated in cradle 122, ECG waveforms 110 may be provided directly (via asuitable complementary connectors 128A, 128B) to display 120—i.e.without wireless communication.

Base unit 102 may comprise suitably configured hardware and/or softwarecomponents for processing signals from electrode units 104 and forgenerating corresponding ECG waveform(s) 110 for display on display 120.In the illustrated embodiment, such components include: a controller112, signal processing hardware 114, data storage 116, communicationshardware 130 and user interface components 132. For simplicity, only anumber of components germane to the present invention are described indetail here. It will be appreciated by those skilled in the art thatbase unit 102 may comprise other electronic components suitable foroperation as described herein. These components may be configured toprovide particular functionality using suitably coded software (notexplicitly shown). Controller 112 may interact with and control theother functional components of ECG system 100. By way of non-limitingexample, controller 112 may comprise any suitable controller, such as,for example, a suitably configured computer, microprocessor,microcontroller, field-programmable gate array (FPGA), other type ofprogrammable logic device, pluralities of the foregoing, combinations ofthe foregoing, and/or the like. Controller 112 may have access tosoftware which may be stored in computer-readable memory (not shown)accessible to controller 112 and/or in computer-readable memory that isintegral to controller 112. Controller 112 may be configured to read andexecute such software instructions and, when executed by controller 112,such software may cause controller 112 to implement one or more of themethods described herein.

Signal processing hardware 114 may comprise any suitable analog ordigital signal conditioning and/or signal processing components forgenerating ECG waveforms 110 from the signals obtained from electrodeunits 104. By way of non-limiting example, signal processing hardware114 may comprise amplifiers, buffers, filters, analog to digitalconverters, suitably configured digital signal processors and/or thelike. Data storage 116 may comprise any suitable memory (e.g. solidstate memory) that may be used to store digital ECG data. In someembodiments, data storage 116 may be integrated into other components(e.g. controller 112 or signal processing hardware 114). In someembodiments, data storage 116 is not necessary.

Communications hardware 130 may comprise suitable hardware (e.g. WANinterfaces, LAN interfaces) for wireless communication according to oneor more wireless digital communications protocols. Non-limiting examplesof such protocols, include: a suitable Bluetooth communication protocol;wireless USB protocol; 802.11 wireless protocol; Zigbee protocol and/orthe like. In some embodiments, display 120 may not be detachable frombase unit 102 in which case display 120 may be connected via suitableelectrical contacts. In some embodiments, display 120 may be removablefrom cradle 122, but attached to base unit 102 with a signalcommunication cable or the like. In such embodiments, some or all ofcommunications hardware 130 may not be required. In some embodiments,communications hardware 130 may facilitate communication of ECG data(e.g. data stored in data storage 116, real time ECG waveforms 110and/or the like) from base unit 102 to an external ECG system 124. Insome embodiments, where external ECG system 124 is not capable ofwireless communications or of wireless digital communications, ECGsystem 100 may comprise a suitable external ECG system communicationscomponent 124A which may be used to communicate with communicationshardware 130 and to convert any received data/signals fromcommunications hardware into a format capable of being interpreted byexternal ECG system 124. External ECG system communications component124A may comprise hardware similar to any of the hardware describedherein for base unit 102.

In some embodiments, communications hardware 130 may facilitatecommunication of ECG data (e.g. data stored in data storage 116, realtime ECG waveforms 110 and/or the like) from base unit 102 to anotherdevice 126A (e.g. a computer or the like) via a network 126 or via adirect communication link (not shown) for further processing and/ordisplay. By way of non-limiting example, network 126 may comprise: alocal area network (LAN), such as a hospital network, a work placenetwork or the like; or a wide area network (WAN), such as the internet,a cellular network or the like). In some embodiments, communicationshardware 130 may additionally or alternatively facilitate wiredcommunication with external ECG system 124 or with another device 126A(e.g. a computer or the like) via a network 126.

Display 120 together with user interface inputs 130 may be used (bycontroller 112) to implement a text-based or graphical user interface(UI). User interface inputs 130 may comprise any suitable pointingdevice, buttons, touch screen and/or the like through which anindividual (e.g. a medical professional) can interact with and controlECG system 100. By way of non-limiting example, a medical professionalcould control such a user interface to: freeze ECG waveform 110 ondisplay 120; view historical waveforms 110 or pulses; switch between thewaveforms 110 of different leads; toggle between views of single ECGwaveforms 110 or multiple ECG waveforms 110; zoom in on ECG waveform 110on display 120; measure characteristics (e.g. amplitude and/orfrequency) of ECG waveform 110; communicate with other devices (e.g.external ECG system 124 and/or another device via network 126); print tosuitably configured printer device; toggle a “graph-paper” background ondisplay 120; identify abnormal ECG rhythms; display measurementsassociated with other diagnostic equipment (explained in more detailbelow) which may be connected to ECG system 100 (e.g. blood pressure,blood sugar, pulse oximetry (SpO₂), body temperature and/or the like);display alarms or alerts associated with abnormalities measured by suchother diagnostic equipment; provide temporal information (e.g. clocks orstopwatches), alarms and/or alerts; and/or the like.

Base unit 102 may comprise a number of additional connectors 108 foroptional connection to additional electrode units 104 (not shown). Forexample, in the illustrated embodiment, base unit comprises sevenadditional connectors 108 for connection to seven additional electrodeunits 104. With a total of ten electrode units 104, ECG system can beconfigured to provide the so-called “12 lead” ECG functionality. In someembodiments, additional connectors 108 may be used to connect to one ormore additional electrode units 104 which may be used to sense othertypes of electrically-based physiological phenomena (physiologicalelectrical activity), such as electrical activity of the brain (e.g. EEGdata), electrical activity associated with skeletal muscles (e.g. EMGdata), electrical activity of the eye (e.g. EOG data) and/or the like.

Base unit 102 may also comprise suitable connections 134 for connectingto other medical equipment (not shown). Such connections 134 may be usedto accept data from such equipment (e.g. from medical diagnosticequipment). By way of non-limiting example, such medical diagnosticequipment may comprise a blood pressure cuff, a glucometer, a pulseoximetry (SpO₂) monitor, and end-tidal carbon dioxide (ETCO₂) monitor, athermometer and/or the like. Connections 134 may also be used for othermedical equipment. In some embodiments, connections 134 may be used toconnect to a pair of defibrillator pads or paddles which may be used todeliver defibrillation shock(s) (e.g. pacing defibrillation, cardioversion defibrillation and/or automatic external defibrillation) to anindividual. In some embodiments, connections 134 may be used to provideother electrically sensitive electrode units, which may be similar toelectrode units 104 and may be used to sense heart muscle activity (e.g.ECG data), but may additionally or alternatively be used to sense othertypes of electrically-based physiological phenomena (physiologicalelectrical activity), such as electrical activity of the brain (e.g. EEGdata), electrical activity associated with skeletal muscles (e.g. EMGdata), electrical activity of the eye (e.g. EOG data) and/or the like.While not expressly shown, base unit 102 may comprise a separaterechargeable battery which may be used to deliver such defibrillationshock(s).

FIG. 4B schematically illustrates an ECG system 200 according to aparticular embodiment. ECG system 200 is similar in many respects to ECGsystem 100 described above and the same reference numerals are used torefer to features of ECG system 200 that are similar to features of ECGsystem 100. Like ECG system 100, ECG system 200 comprises a base unit202 and two or more electrode units 204A, 204B (collectively andindividually, electrode units 204). ECG system 200 differs from ECGsystem 100 principally in that electrode units 204 are integral withbase unit 202. Other than being located within base unit 202, electrodeunits 204 may be substantially similar to electrode units 104 describedherein and may comprise any features and/or variations of electrodeunits 104 described herein.

In the illustrated embodiment, ECG system is shown as having a thirdelectrode unit 104C which attaches to base unit 202 via cable 106C andconnector 108C to facilitate operation of ECG system 200 in anEinthoven's triangle configuration. Third electrode unit 104C may besubstantially similar to electrode units 104 described herein and maycomprise any features and/or variations of electrode units 104 describedherein. In some embodiments, third electrode unit 104C is not necessaryand system 100 may use as few as two electrode units 204. In someembodiments, a third electrode unit 204 may be provided as an integralpart of base unit 202 (i.e. similar to electrode units 204 of the FIG.4B embodiment). Like ECG system 100, ECG system 200 comprises connectors108 for accepting additional electrode units 104 to provide additionalleads and corresponding additional views of heart muscle electricalactivity.

In some embodiments, electrode units 204 may be detachable from baseunit 202—e.g. to sense electrical activity of the heart at differentlocations away from base unit 202. For example, electrode units 204 maybe provided in suitable sockets (not expressly shown), so that they canfunction to sense heart activity within their corresponding sockets. Butelectrodes 204 may be removed from their sockets, so that they can beconnected to base unit 202 by suitable cables and connectors (similar tocables 106 and connectors 108 described above for electrode units 104).In this manner, electrode units 204 may also be able to sense electricalactivity at locations away from base unit 202.

In other respects, ECG system 200 may be substantially similar to ECGsystem 100 described herein.

FIG. 4C schematically illustrates an ECG system 300 according to aparticular embodiment. ECG system 300 is similar in many respects to ECGsystems 100, 200 described above and the same reference numerals areused to refer to features of ECG system 300 that are similar to featuresof ECG systems 100, 200. Like ECG system 200, ECG system 300 comprises abase unit 202 and two or more electrode units 204 that are integral withbase unit 202. ECG system 300 differs from ECG systems 100, 200described herein in that ECG system comprises a third electrode unit304C which is connected to base unit 202 via connector 108C andextension arm 306C. Third electrode unit 304C may be substantiallysimilar to electrode units 104 described herein and may comprise anyfeatures and/or variations of electrode units 104 described herein.Third electrode unit 304C may permit ECG system 300 to operate in anEinthoven's triangle configuration. However, in ECG system 300 of theFIG. 4C embodiment, extension arm 306C is fabricated from flexible,semi-rigid (e.g. limited elasticity) material that may be deformed bythe ECG operator and, once deformed, may retain its shape so thatelectrode unit 304C remains in a desired location relative to theindividual's body 101 until extension arm 306C is intentionally reshapedor repositioned by the ECG operator. Suitable materials for extensionarm 306C may include, for example, memory plastic and/or the like. Insome embodiments, extension arm 306C may comprise a casing having theflexible, semi-rigid (e.g. limited elasticity) properties which may inturn house a cable (e.g. similar to cable 106 described herein). It willbe appreciated that in some embodiments, any electrode units 104described as being connected to their respective base units may beconnected via flexible, semi-rigid (e.g. inelastic) extension armssimilar to extension arm 306C.

In other respects, ECG system 300 may be substantially similar to ECGsystems 100, 200 described herein.

FIG. 4D schematically illustrates an ECG system 400 according to aparticular embodiment. ECG system 400 is similar in many respects to ECGsystems 100, 200, 300 described above and the same reference numeralsare used to refer to features of ECG system 400 that are similar tofeatures of ECG systems 100, 200, 300. ECG system 400 comprises a baseunit 402 and two or more electrode assemblies 404A, 404B, 404C(collectively and individually, electrode assemblies 404). Eachelectrode assembly 404A, 404B, 440C may comprise a correspondingelectrode unit 104A, 104B, 104C which may be similar to electrode units104 described herein and which may comprise any features and/orvariations of electrode units 104 described herein. Each electrodeassembly 404A, 404B, 404C may also comprise corresponding signalprocessing components 406A, 406B, 406C (collectively and individually,signal processing components 406) and communications components 408A,408B, 408C (collectively and individually, communications components408). Signal processing components 406 may comprise any suitable analogor digital signal components for conditioning and/or processing thesignals obtained from electrode units 104. By way of non-limitingexample, signal processing components 408 may comprise amplifiers,buffers, filters, analog to digital converters, suitably configureddigital signal processors and/or the like. Communications components 408may comprise any suitable hardware for analog or digital wirelesscommunication of signals obtained from electrode units 104 (andprocessed by signal processing components 406) back to base unit 402. Inthis manner, base unit 402 may be positioned at a location 105 away fromthe individual's body 101. In some embodiments, electrode assemblies 404may be electrically connected to one another (e.g. to provide a commonground or reference potential). In some embodiments, electrodeassemblies 404 may share some of signal processing components 406 and/orcommunications components 408.

Electrode assemblies 404 may be located relative to an individual's body101 (as discussed in more detail below) to generate signals indicativeof electrical activity of the individual's heart at their correspondinglocations and may wirelessly communicate these signals back to base unit402 at a location 105 away from the individual's body 101. In theillustrated embodiment of FIG. 4D, ECG system 400 is shown as havingthree electrode assemblies 404A, 404B, 404C which may be used in anEinthoven's triangle configuration. In some embodiments, third electrodeassembly 404C is not necessary and system 400 may use as few as twoelectrode assemblies 404. In some embodiments, system 400 may beprovided with more than three electrode assemblies 404 to provideadditional leads and corresponding additional views of heart muscleelectrical activity. In some embodiments, electrode assemblies 404 maycomprise suitably configured controllers (not shown) which may controlsignal processing components 406 and/or communications components 408.

Communications hardware 430 (and associated software) of ECG system 400may differ from that of ECG systems 100, 200, 300 in that communicationscomponents 430 of ECG system 400 may be additionally configured tocommunicate wirelessly with electrode assemblies 404. In other respects,ECG system 400 may be substantially similar to ECG systems 100, 200, 300described herein.

In some embodiments, ECG system 400 is operatively connected to avehicle's embedded software system such that ECG system 400 cancommunicate with the vehicle's systems to effect changes in thevehicle's physical parts, such as the brakes, engine, and the like. Whena vehicle operator steps into the vehicle (e.g. possibly, but notnecessarily before starting the vehicle), a vehicle operator may, in oneembodiment, be asked to place one electrode unit 104 and/or oneelectrode assembly 404 onto the vehicle operator's chest (e.g. via avehicle restraint (seat belt) and/or the like operating in a currentsensing mode, a contact field-sensing mode or a non-contactfield-sensing mode, in some embodiments) and one or more electrode units104 and/or electrode assemblies 404 embedded in the back of the vehicleoperator's seat (operating in a non-contact field sensing mode, in someembodiments). It will be appreciated that, in some embodiments,additional or alternative locations of electrode units 104 and/orelectrode assemblies 404 could be used and that such electrode units(depending on their locations) could operate in current-sensing mode,field-sensing contact mode or field sensing non-contact mode. In someembodiments, electrode assemblies 404 operating only in field sensingnon-contact mode are used in the vehicle and the vehicle operator willnot need to physically attach electrode units 104 and/or electrodeassembly 404 to the operator's chest. Signals detected by electrodeunits 104 and/or electrode assemblies 404 may be used to generatecorresponding ECG signals (e.g. ECG waveforms 110), which may beanalyzed (e.g. by controller 112, other controllers in ECG system 400,or external ECG systems 124 (communicating with ECG system 400 throughcommunications component 124A)) to determine the state of the vehicleoperator's heart and the vehicle operator's respiration patterns. Theanalysis may be done through the use of software algorithms and mayinclude comparison to other data sets. Where the ECG waveforms 110indicate the individual is incapacitated or is not in the propercondition to operate the vehicle, controller 112 communicates with thevehicle's on board system, which may act in accordance with instructionsfrom controller 112. In some embodiment, if the ECG waveform 110indicates that the vehicle operator is going to fall asleep, is drowsy,or is already asleep, controller 112 may communicate an alarminstruction to the vehicle system, and the vehicle system, uponreceiving the instruction, will sound an alarm insider the vehicle orincrease the volume of the radio and/or music playing in theentertainment system to wake the vehicle operator. In some embodiments,the alarm may comprise a vibration of the operator's seat to wake thevehicle operator. In some embodiments, the vehicle's infotainment systemmay ask the vehicle operator questions or require the vehicle operatorto issue commands in order to wake, keep awake or otherwise maintain thealertness of the vehicle operator. In some embodiments, if the ECGwaveform 110 indicates that the vehicle operator is incapacitated,controller 112 will not permit the vehicle to start or will communicatea stop instruction to the vehicle's system, and the vehicle's systemwill turn on the vehicle's emergency stop lights and slowly brake thevehicle to a stop. In some embodiments, ECG system 400 may interface orcommunicate with a vehicle's safety systems, such as active cruisecontrol system, lane departure warning system, frontal collision warningsystem, precrash system, collision mitigating system, collisionavoidance system, and/or the like to reduce the likelihood of anaccident's occurrence while the vehicle operator is incapacitated orotherwise unable to operate the vehicle. ECG system 400 may alsocommunicate the vehicle operator's location and condition to emergencydispatchers such that emergency personnel can attend to the vehicle'svehicle operator quickly. Data from such vehicular ECG systems may berecorded—e.g. for forensic analysis, data analytics and/or the like.Systems 100, 200 and/or 300 and/or any of the EEG, EOG or EMG systemsdescribed herein could be used in vehicle in a similar way to system 400described herein.

FIG. 5A is a block diagram showing one implementation of a signalprocessing system 500A for processing data from electrode units 104according to a particular embodiment. Signal processing system 500A mayprovide some of signal processing hardware 114 used with any of the ECGsystems (e.g. ECG systems 100, 200, 300, 400) described herein. In someimplementations, various portions of signal processing system 500A (e.g.amplifiers 504, ADCs 506 and or the like) could be implemented as partsof electrode units 104 (as opposed to being implemented as parts of baseunits 102, 202, 302, 402). In general, it will be appreciated that thecomponents shown in the FIG. 5A schematic illustration are functionalcomponents which could be implemented by various forms of suitablyconfigured hardware.

Signal processing system 500A receives analog data from electrode units104. Each electrode unit 104 generates a corresponding analog signal 502which is amplified by a corresponding amplifier 504 and digitized by acorresponding analog-to-digital converter (ADC) 506 before beingprovided (as a digital signal 508) to digital signal processor (DSP)510. In some embodiments, DSP 510 may include integral ADC converters506. DSP 510 may be configured to generate leads from digital signals508 and to generate corresponding ECG data (e.g. ECG waveform 110).Digital signal processor 510 may additionally be configured to filterthe various digital signals 508 (and/or combinations of such signals).For example, DSP 510 may be configured to filter various signals (orcombinations of signals) to remove or mitigate the effects of breathingand/or other sources of artifacts. DSP 510 may additionally oralternatively function to apply active noise cancellation algorithms,based on inverted ambient noise data. DSP 510 may additionally oralternatively scale signals 508 received from electrode units 104operating in different modes (explained in more detail below). DSP 510may additionally or alternatively provide synchronization functionalityby introducing time delays to one or more of signals 508. Such timedelays may be determined based on temporal correlation functions asbetween signals 508 and/or based on feature (e.g. edges, peaks and/orthe like) detection within signals 508. DSP 510 may also combine thevarious signals 508 to generate leads and corresponding ECG waveforms.

As is known in the art of digital signal processing, DSP 510 may beconfigured to process signals using functionality such as sample andhold functions, data acquisition functions, multi stage filtering andbandwidth limiting, filtering based, for example, on a rolling window,averaging functions, peak detection, temporal alignment of signalsprovided by different electrode units 104, positive and negative edgedetection, time duration of PQRST portion of the ECG signal andrelationship between them. Digital signal processor 510 may becontrolled by controller 112. In some embodiments, however, DSP 510 andcontroller 112 may be implemented by the same hardware. In the FIG. 5Aembodiment, DSP 510 has access to data storage 116. In some embodiments,all or part of data storage 116 may be integral to DSP 510. DSP 510 mayoutput ECG data to data storage 116 and/or to display 120 (viacommunications components 130) and may provide the backgroundfunctionality for such outputs. As discussed above, in some embodimentswhen display 120 is located in cradle 122 or when display is integralwith base unit 102, ECG data may be provided directly to display 120without involving communications hardware 130.

FIG. 5B is a block diagram showing one implementation of a signalprocessing system 500B for processing data from electrode units 104according to another particular embodiment. Signal processing system500B may provide some of signal processing hardware 114 used with any ofthe ECG systems (e.g. ECG systems 100, 200, 300, 400) described herein.Signal processing system 500B receives analog data from electrode units104. Each electrode unit 104 generates a corresponding analog signal 502which is received at analog signal conditioning block 512. Analog signalconditioning block 512 comprises various amplifiers (e.g. summingamplifiers and/or differential amplifiers and/or inverting amplifiers)which combine analog signals 502 in various ways known in the art togenerate leads 514. Each lead 514 is then amplified by a correspondingamplifier 516 and digitized by a corresponding analog-to-digitalconverter (ADC) 518 before being provided (as a digital lead signal 520)to digital signal processor (DSP) 522. Digital signal processor 522 maythen be configured to use digital lead signals 520 to generatecorresponding ECG data (e.g. ECG waveform 110). Other than for receivingleads (as opposed to signals from electrode units 104), DSP 522 maycomprise and provide functionality similar to that described above forDSP 510. In some embodiments, signal processing system 500B may be usedto generate data from other types of electrically-based physiologicalphenomena (physiological electrical activity), such as electricalactivity of the brain (e.g. EEG data), electrical activity associatedwith skeletal muscles (e.g. EMG data), electrical activity of the eye(e.g. EOG data) and/or the like.

A description of electrode units is now provided. For the sake ofbrevity, the description of electrode units refers to electrode units104, it being understood that electrode units 204, 304 may have similarfeatures. For the sake of brevity, the bulk of the description ofelectrode units 104 assumes that electrode units 104 are used to measurethe electrical activity of the heart muscle (e.g. ECG data). However, asmentioned above and discussed in more detail below, electrode units 104may additionally or alternatively be used to sense other types ofelectrically-based physiological phenomena (physiological electricalactivity), such as electrical activity of the brain (e.g. EEG data),electrical activity associated with skeletal muscles (e.g. EMG data),electrical activity of the eye (e.g. EOG data) and/or the like. In someembodiments, one or more of electrode units 104 comprise resistivesensor elements for sensing the current through or voltage across theresistive sensor element. Electrode units 104 which comprise resistivesensor elements may be referred to herein as current-sensing electrodeunits (without loss of generality that the voltage across resistivesensor elements could be detected). Current sensing electrode units 104operate by placing the resistive sensor element in direct contact with aperson's skin. In some embodiments, one or more of electrode units 104comprise capacitive sensor elements which detect the presence ofelectric field. Electrode units 104 which comprise capacitive sensorelements may be referred to herein as field-sensing electrode units.Unlike resistive sensor elements, the capacitive sensor elements offield-sensing electrode units 104 do not require direct contact with theskin and may function by being placed close to the person's body (e.g.overtop of clothes, clothing accessories, equipment (including sportsand soldier equipment) and/or the like), in (including embedded ormounted within) the backrest or bottom portion of a seat or chair (e.g.,seats (e.g. operator seat(s) and/or other seat(s)) or seat restraints(e.g. seat restraints, such as a seat belt, safety belt, and/or thelike) in a vehicle such as a car, plane, helicopter, motorcycle, truck,boat, cart, or the like, car seats, strollers, and/or the like), in thecontrols of a vehicle (e.g., in the handle bars of a motorcycle, in thesteering wheel of a car, and/or the like), in a bed (e.g. a hospitalbed, crib, bed frame, and/or the like), and/or the like. In someembodiments, electrode units 104 are incorporated into emergencyresponse vehicles, such as police cars, ambulance, fire engines, and/orthe like, and military vehicles, such as tanks, armored vehicles,infantry vehicles, amphibious vehicles, trooper carriers, engineeringvehicles, military aircraft and/or the like. As discussed in more detailbelow, field-sensing electrode units may operate in a contact mode (i.e.in direct contact with a person's skin) or a non-contact mode (i.e. notin direct contact with a person's skin).

ECG systems 100, 200, 300, 400 described herein may use either (or both)of current-sensing electrode units 104 and field-sensing electrode units104. Each of connectors 108 may be capable of accepting eithercurrent-sensing electrode units 104 or field-sensing electrode units104. In particular embodiments, a combination of current-sensingelectrode units 104 and field-sensing electrode units 104 may be used inany of ECG systems 100, 200, 300, 400 to monitor the heart muscleelectrical activity of an individual. The choice of which particularelectrode unit 104 may depend on the preferences of the system'soperator, the electrode units that are currently available, and thecircumstances (e.g. whether it is difficult to remove the individual'sclothing, or whether the individual already has exposed skin at thedesired vantage points).

In particular embodiments, one or more of electrode units 104 that isused in systems 100, 200, 300, 400 may comprise a multi-mode electrodeunit 104 which can be configured to operate in one of a plurality ofdifferent modes. Such multi-mode electrode units 104 may operate ascurrent-sensing electrode units by providing a resistive sensor elementplaced in direct contact with an individual's skin (i.e. under theindividual's clothing (or at least with no intervening clothing betweenthe sensor and the individual's skin)). Such multi-mode electrode units104 may also operate as field-sensing electrode units which involveplacing a capacitive sensor element in direct contact with anindividual's skin (i.e. under the individual's clothing (or at leastwith no intervening clothing between the sensor and the individual'sskin)). When such field-sensing electrode units are placed in directcontact with an individual's skin (i.e. under the individual's clothing(or at least with no intervening clothing between the sensor and theindividual's skin)), such electrode units may be referred to herein asoperating in “contact” mode. Such multi-mode electrode units 104 mayalso operate as field-sensing electrode units which involve placing acapacitive sensor element on top of the individual's clothing and notdirectly against the skin. When the individual's clothing is locatedbetween the electrode unit and the individual's skin, the electrode unitmay be referred to herein as operating in “non-contact” mode. Sincecurrent-sensing electrode units typically require direct contact withthe skin (i.e. no intervening clothing) to detect a signal, it is notnecessary to describe current-sensing electrode units as operating incontact mode or non-contact mode, it being understood that when acurrent-sensing electrode unit 104 is operative, it operates in contactmode.

FIGS. 6A and 6B show a multi-mode electrode unit 600, which may be usedfor electrode unit 104 of any of ECG systems 100, 200, 300, 400.Multi-mode electrode unit 600 may be configured for operation infield-sensing contact mode, field-sensing non-contact mode and/orcurrent-sensing mode. Any one or more of electrode units 104, 204, 304may comprise an electrode unit 600 of the type shown in FIGS. 6A and 6B.Electrode unit 600 comprises a clamp portion 602 and a sensor portion604 which is removably attached to clamp portion 602. As discussed inmore detail below, sensor portion 604 comprises a capacitive sensorelement 606 which permits electrode unit 600 to operate in afield-sensing contact mode (where sensor portion 604 is in directcontact with the individual's skin) or a field-sensing non-contact mode(where sensor portion 604 is located outside of the individual'sclothing or otherwise is not in contact with the individual's skin).Further, at least one of clamp portion 602 and sensor portion 604comprise a mechanism for electrical connection with a resistive sensorelement 608 (FIG. 6B) which permits electrode unit 600 to operate in acurrent-sensing mode. Because electrode unit 600 can be placed either onskin or atop clothing and because electrode unit 600 can operate as acurrent-sensing electrode unit or a field-sensing electrode unit,electrode unit 600 is versatile and can be used in a range of differentsituations. For example, in some situations it may be desirable or moreconvenient to leave the clothing on an individual and to place theelectrode unit 600 on top of the individual's clothing. In othersituations the individual's skin may be exposed at desired vantagepoints—for example, the individual's torso may be exposed to allow theperformance of a procedure (such as, by way of non-limiting example,defibrillation, CPR, insertion of a chest tube and/or the like) whichrequires direct contact with or exposure of the skin—and so in thosecases it may be convenient to place electrode unit 600 directly againstthe skin.

When electrode unit 600 operates in a field-sensing, non-contact mode,electrode unit 600 is placed over the individual's clothing. As seen inFIGS. 6A and 6B, electrode unit 600 comprises a clamp 610. In theillustrated embodiment of FIGS. 6A and 6B, clamp 610 comprises a pair ofarms 610A, 610B which are pivotally connected to one another at pivotjoint 612 and which are biased toward each other (e.g. by a suitablyconnected spring, a suitable deformable element and/or the like (notshown)) so that clamp 610 is biased toward a closed configuration. Arms610A, 610B can be used to grip a part of the individual's clothing toattach the electrode unit 600 to the individual's clothing at thedesired vantage point while the electrode unit 600 is being operated infield-sensing, non-contact mode. More particularly, when electrode unit600 is operated in field-sensing, non-contact mode, a portion of theindividual's clothing may be grasped between arms 601A, 601B of clamp610 and proximate surface 614 of sensor portion 604 may be positioneddirectly atop the individual's clothing. This permits capacitive sensorelement 606 to sense the electric field associated with the individual'sheart-muscle activity and to provide a corresponding signal on one ormore conductors of cable 624 which may be conveyed back to the base unitof the ECG system. Cable 624 may comprise one of cables 106 describedabove (see FIG. 4A, for example).

In some embodiments, sensor portion 604 is removably attached to clampportion 602, so that sensor portion 604 may optionally be detached fromclamp portion 602 (FIG. 6B)—e.g. for use of sensor portion 604 infield-sensing, contact mode. More particularly, as can be seen bycomparing FIGS. 6A and 6B, sensor portion 604 may be attached to clampportion 602 (e.g. retained in cavity 618 in the particular case of theillustrated embodiment) to provide a unitary electrode unit 600 andsensor portion 604 may also be detached from clamp portion 602 toprovide sensor portion 604 separately. When sensor portion 604 isseparated from clamp portion 602, the proximate surface 614 of sensorportion 604 may be placed into contact with an individual's skin topermit capacitive sensor element 606 to sense the electric fieldassociated with the individual's heart-muscle activity in a contact modeand to provide a corresponding signal on one or more of the conductorsof cable 624 which is conveyed back to the base unit of the ECG system.

It is not necessary that sensor portion 604 be removed from clampportion 602 for operation of electrode unit 600 in field-sensing,contact mode. In some embodiments, electrode unit 600 (including clampportion 602 and sensor portion 604) may be located such that proximatesurface 614 of sensor portion 604 is adjacent the individual's skin. Forexample, as shown in FIG. 6B, cavity 618 (in which sensor portion 604 isretained) comprises a rim 618A around its peripheral edge, but rim 618Adefines an opening 619 which permits proximate surface 614 of sensorportion 604 to directly contact an individual's skin. With thisconfiguration, capacitive sensor element 606 is able to sense theelectric field associated with the individual's heart-muscle electricalactivity in a field-sensing, contact mode (and to provide acorresponding signal to the ECG base unit on cable 624) even when sensorportion 604 is attached to clamp portion 602. Similarly, it is notnecessary to operate in a field-sensing contact mode when sensor portion604 is separated from clamp portion 602. When sensor portion 604 isseparated from clamp portion 602, it is still possible to use sensorportion 604 in a field-sensing non-contact mode.

Sensor portion 604 and/or clamp portion 602 may comprise a lockingmechanism 616 for keeping sensor portion 604 attached to clamp portion602. In the FIG. 6A, 6B embodiment, sensor portion 604 is received incavity 618 of clamp portion 602 and a spring-biased locking mechanism616 extends (radially inwardly in the case of the illustratedembodiment) over an edge of distal surface 620 of sensor portion 604.When spring-biased locking mechanism 616 extends over the edge of distalsurface 620 of sensor portion, locking mechanism 618 holds sensorportion 604 in cavity 618 (e.g. against rim 618A) and thereby lockssensor portion 604 into attachment with clamp portion 602. To detachsensor portion 604 from clamp portion 602, an operator may slide lockingmechanism 616 against the spring bias (radially outwardly in the case ofthe illustrated embodiment) to remove sensor portion 604 from cavity618. Some embodiments may comprise a plurality of spring-biased lockingmechanisms 616. In some embodiments, sensor portion 604 may be locked toclamp portion 602 using different additional or alternative lockingmechanisms. In the illustrated embodiment, when sensor portion 602 islocated in cavity 618, cable 624 which is attached to sensor portion 604runs through a channel 611 formed in a sidewall of cavity 618 of clampportion 602. In other embodiments, cable 624 may run through differentfeatures when sensor portion 604 is attached to clamp portion 602.

In some embodiments, when electrode unit 600 is being used infield-sensing, contact mode, electrode unit 600 (or sensor portion 604of electrode unit 600) may be adhered to the skin of the individualusing adhesive tape, adhesive stickers, a suctioning mechanism or othermeans. For example, a double-sided adhesive sticker or tape can beplaced between the individual's skin and electrode unit 600 (or sensorportion 604 of electrode unit 600) to adhesively connect electrode unit600 (or sensor portion 604 of electrode unit 600) to the individual'sskin. Similarly, adhesive tape can be applied over top of electrode unit600 to tape electrode unit 600 in contact with an individual's skin andto permit electrode unit 600 to be used in field-sensing contact mode.In some embodiments, electrode unit 600 (or sensor portion 604 ofelectrode unit 600) may comprise a suction cup or suction hole (notshown) fluidly coupled to a suctioning bulb (not shown). The bulb may besqueezed prior to placement of the suction cup/hole on the individual'sskin. Once the suction cup/hole is placed on the skin, the bulb isreleased to create a suctioning connection between the suction cup/holeand the skin, thereby holding electrode unit 600 (or sensor portion 604of electrode unit 600) against the individual's skin. In someembodiment, a piece of tape may be applied to the individual's skin withan end portion of the tape extending away from the individual's skin.The end portion of the tape may then be adhered to a side surface 615 ofsensor portion 604 or the end portion of the tape may be gripped betweenarms 610A, 610B of clamp 610 to help hold electrode unit 600 (or sensorportion 604 of electrode unit 600) against the individual's skin tothereby facilitate operation in field-sensing contact mode.

In addition to operating in field-sensing non-contact mode andfield-sensing contact mode as discussed above, electrode unit 600 alsooperates in current-sensing mode. More particularly, at least one ofclamp portion 602 and sensor portion 604 comprise a mechanism forelectrical connection with a resistive sensor element 608 (FIG. 6B)which permits electrode unit 600 to operate in a current-sensing mode.In the illustrated embodiment, sensor portion 604 of electrode unit 600comprises a snap-mechanism 622 for connection to a complementarysnap-mechanism 626 on resistive sensor element 608. In the illustratedembodiment, snap-mechanism 622 is located on distal surface 620 ofsensor portion 604. In other embodiments, snap mechanism 622 may belocated on other surface(s) of sensor portion 604 and/or clamp portion602. Snap mechanism 622 is in electrical contact with one or moreconductors in cable 624 so that a signal may be conveyed back to thebase unit of the ECG system via cable 624. The cable 624 conductor thatis in electrical contact with snap mechanism 622 may be (but need notbe) the same cable 624 conductor that is in electrical contact with thecapacitive sensor element 606.

FIG. 7A shows a variety of resistive sensor elements 608A, 608B, 608C(collectively and individually, resistive sensor elements 608) ofdifferent shapes and sizes, each with a corresponding snap-mechanism626A, 626B, 626C (collectively and individually, snap-mechanisms 626).In the current North American industry standard, snap-mechanisms 626 ofresistive sensor elements are male snap-mechanisms 626. Accordingly,snap-mechanism 622 of electrode unit 600 may comprise a femalesnap-mechanism sized and shaped to mate with male snap-mechanisms 626 ofresistive sensor elements 608. Snap-mechanisms 622, 626 arecomplimentary to one another, so that when they are engaged, there is asmall amount of deformation of one or both of snap-mechanisms 622, 626such that restorative forces associated with that deformation tend tolock snap-mechanisms 622, 626 to one another.

In use, a resistive sensor element 608 is connected to electrode unit600 via a connection of snap-mechanisms 622, 626 and then the side ofresistive sensor element 608 opposite snap-mechanism 626 is adhered tothe skin of the individual for operative in current-sensing contactmode. Typically, resistive sensor elements 608 comprise an adhesive“peel and stick” type backing which may be used for this purpose. Theheart muscle electrical activity signal detected by resistive sensorelement 608 is conveyed via the contact between snap-mechanism 622, 626to cable 624 and to the base unit of the ECG system. When operating incurrent-sensing mode, sensor portion 604 of electrode unit 600 may beremoved from clamp portion 602 of electrode unit 600 in the same mannerdiscussed above. This is not necessary, however, and electrode unit 600may operate in current-sensing mode with sensor portion 604 connected toclamp portion 602.

Resistive sensor elements 608 having snap-mechanisms 626 are common, butare not the only type of resistive sensor element. FIG. 7B depictsanother type of resistive sensor element 630 which comprises an activesurface 632 which may be adhered to the individual's skin (e.g. with apeel and stick type adhesive or a suitable external adhesive). Resistivesensor element 603 also comprises a tab 634, such that when activesurface 632 is adhered to the individual's skin, tab 634 may be bent (ormay otherwise extend) away from the individual's body. Multimodeelectrode unit 600 may also function in a current-sensing contact modewith resistive sensor elements 630. More particularly, tab 634 ofresistive sensor element may be clamped between the arms 610A, 610B ofclamp 610. One or both of the engagement surfaces of clamp 610 may beprovided with electrical contacts 636A, 636B (collectively andindividually, clamp contacts 636). Clamp contacts 636 may beelectrically connected to transmit a current-sensing contact signalthrough electrode unit 600 and a conductor of cable 624 back to the baseunit of the ECG system.

In the case of the illustrated embodiment, clamp contacts 636 are inelectrical contact with electrical contact 638 (e.g. via a suitable wireor other conductor within one or both arms 610A, 610B of clamp 610.Electrical contact 638 may comprise any suitable electrical contact pin,plate, socket, shoe and/or the like. In the illustrated embodiment,electrical contact 638 is located on a wall of cavity 618. Sensorportion 604 may be provided with a complementary electrical contact (notshown in the illustrated view) which is in electrical contact with oneof the conductors of cable 624. The electrical contact in sensor portion604 may be complementary to electrical contact 638 and may comprise anysuitable electrical contact pin, plate, socket, shoe and/or the like. Insome embodiments, one or both of contact 638 and the contact in sensorportion 604 may be spring-loaded. When sensor portion 604 is connectedto clamp portion 602 (e.g. sensor portion 604 is located in cavity 618as shown in FIG. 6A of the illustrated embodiment), the electricalcontact shoe of sensor portion 604 makes electrical contact withelectrical contact shoe 638 of clamp portion 602, thus completing anelectrical contact from clamp contacts 636, through electrical contactshoe 638 of clamp portion 602 and the electrical contact shoe of sensorportion 604 to a conductor of cable 624 and back to the base unit of theECG system. In this manner, electrode unit 600 may work incurrent-sensing contact mode with resistive sensor element 630 and mayconvey heart activity signals back to the base unit of the ECG system.

In electrode unit 600 of the FIG. 6A, 6B embodiment, clamp 610 servestwo functions. As described above, clamp 610 can be used to attach (e.g.electrically and physically couple) to a current-sensing element 630 sothat electrode unit 600 can be operated in a current-sensing mode.Alternately, clamp 610 can be used to attach electrode unit 600 toclothing when the electrode unit 600 is being operated in afield-sensing non-contact mode. In other embodiments a separate clampingstructure may be provided for each of these functions.

In the illustrated embodiment of FIGS. 6A and 6B, sensor portion 604 isconnected to clamp portion 602 at a location between arms 610A, 610B ofclamp portion 602. This is not necessary. In some embodiments, sensorportion 604 may be connected to other locations on clamp portion 602. Byway of non-limiting example, sensor portion 604 may be connected to anoutside of one of arms 610A, 610B of clamp portion 602 or within one ofarms 610A, 610B of clamp portion 602—i.e. such that sensor portion 604is not located between arms 610A, 610B. In the illustrated embodiment,sensor element 606 is generally round in cross-section. In otherembodiments, sensor element 606 may have a keyed-shape (e.g. aprotrusion from its sidewall 615 (or one of its sidewalls) and acorresponding groove in the sidewall of cavity 618 or vice versa) orsome other cross-sectional shape. In some embodiments, sidewall ofcavity 618 may have a socket shaped to fit sensor element 606. This mayhelp to ensure alignment between electrical contact shoe 638 and thecomplementary electrical contact shoe on sensor portion 604.

In the description of FIGS. 6A and 6B above, signals from resistivesensor elements 608, 630 and from capacitive sensor elements 606 areconveyed back to the base unit of the ECG system via cable 624. Cable624 may comprise one of cables 106 described above. Cable 624 may beconnected to the base unit using a corresponding connector 108 (see FIG.4A, for example). Connectors 108 may comprise multi-conductor (e.g.multi-pin) connectors. Such conductors/pins may comprise, withoutlimitation: a ground pin; one or more current-sensing signal pins (e.g.one pin connected to snap-mechanism 622, one pin connected clampcontacts 636 or one pin connected to both snap-mechanism 622 and clampcontacts 636); and one or more field-sensing signal pins (e.g. connectedto field-sensing element 606). In some embodiments, signals from bothfield-sensing element 606, snap mechanism 622 and clamp contacts 636 maybe connected to the same pin of connectors 108. Cable 624 and connectors108 may comprise additional pins for conveying additional informationfrom electrode unit 600. For example, cable 624 may comprise conductorsand connectors 108 may comprise pins for signals from proximitysensor(s) which may assist with determining the operational modeelectrode unit 600, as explained below. As discussed above in FIG. 4D,electrode unit 600 may be provided as part of an electrode assembly 404where signals are wirelessly conveyed from electrode assemblies 404 tothe base unit of the ECG system. In such embodiments, cable 624 may beconsidered to be a suitable electrical contact to signal processingcomponents 406 of electrode assembly 404—see FIG. 4D.

Where electrode units 104 of ECG systems 100, 200, 300, 400 are providedby multi-mode electrode units 600, an ECG system 100, 200, 300, 400 maybe operated with its electrode units 600 operating in different modes.By way of non-limiting example, electrode units 104A, 104B may operatein any desired combination or permutation of: field-sensing non-contactmode (e.g. over clothing), field-sensing contact mode (i.e. directlyagainst the individual's skin) and current-sensing mode. Similarly, eachof electrode unit 104C and any additional electrode units connected toconnectors 108 may operate in any desired one of: field-sensingnon-contact mode, field-sensing contact mode and current-sensing mode.

The operation of electrode units 104 in different operational modeswithin a particular ECG system 100, 200, 300, 400 may yieldcorresponding electrical signals 502 (see FIGS. 5A, 5B) having differentamplitudes. For example, an electrode unit 104 operating incurrent-sensing mode typically provides a signal 502 which is severalorders of magnitude larger than an electrode unit 104 operating infield-sensing mode. Similarly, an electrode unit 104 operating in afield-sensing contact mode may yield a slightly stronger (e.g. 10%-50%stronger) signal 502 than an electrode unit 104 operating infield-sensing non-contact mode. Signals 502 having different amplitudescan be scaled or the like (e.g. by signal processing hardware 114) tonormalize the signals prior to determining ECG leads (or other combinedor differential signals). Suitable scaling factors can be pre-determinedparameters, user-configurable parameters, system-configurable parametersor determined on an ad hoc basis. In one non-limiting example, digitalsignal processor 510 (FIG. 5A) may be configured to determine theamplitude (e.g. the maximum and minimum level) of each signal from eachelectrode unit 104 and to use this information to scale the signals fromthe various electrodes to normalize the signals to have at leastapproximately the same amplitude. In another non-limiting example, anamplifier or automatic gain control circuit (AGC) in analog signalconditioning circuitry 512 (FIG. 5B) may scale signals from electrodeunits operating in different modes by suitable pre-determined and/orconfigurable factor(s) in effort to normalize the signals from electrodeunits operating in different modes. In some embodiments, scaling may benon-linear.

In some circumstances, it may be desirable to determine the operationalmodes of electrode units 104 so that appropriate adjustments can be madeto their corresponding signals before generating ECG leads (or othercombined or differential signals). For example, where one electrode unit104 is being operated in a field-sensing mode and another electrode unit104 is being operated in a current-sensing mode, it may be desirable toscale the signals to have the same order of magnitude.

As discussed above with reference to FIGS. 6A and 6B, in someembodiments, signals from different operational modes of electrode unit600 can be conveyed on different conductors of cable 624 and conveyed tothe base unit of an ECG system through a different pin of connector 108.In this manner, the ECG system may be able to tell the operational modeof each of its electrode units 104. In some embodiments, an operator mayadditionally or alternatively provide information to the ECG system(e.g. via user inputs 132) to allow the ECG system to determine whichelectrode unit 104 is operating in which operational mode. In someembodiments, the strength of the signal from each electrode unit 104 mayadditionally or alternatively be used by the ECG system to determine theoperational mode of each electrode unit 104. For example, a signalhaving an amplitude above a certain threshold may be indicative of acurrent-sending mode of operation.

In some embodiments, one or more additional sensors (not expresslyshown) can additionally or alternatively be incorporated into electrodeunits 104 to assist with determining the mode of operation. For example,one or more first proximity sensors can be located in electrode unit 104to detect a presence of a resistive sensor element (e.g. a resistivesensor element 608 connected to snap-mechanism 622 or a resistive sensorelement 630 clamped between arms 610A, 610B of clamp 610). If the one ormore first proximity sensors detect a resistive sensor element, then ECGsystem may conclude that electrode unit 104 is operating incurrent-sensing mode. One or more second proximity sensors can belocated in electrode unit 104 to detect the proximity of theindividual's skin. If the one or more second proximity sensors detectthat the individual's skin is within a certain threshold distance andthe one or more first proximity sensors do not detect a resistive sensorelement, then ECG system may conclude that electrode unit 104 isoperating in field-sensing contact mode. On the other hand, if the oneor more second proximity sensors detect that the individual's skin isoutside of the threshold distance and the one or more first proximitysensors do not detect the resistive sensor element, then it may beassumed that the electrode unit 104 is operating in a field-sensingnon-contact mode. In some embodiments, the one or more second proximitysensors may be configured to detect the presence of a clamp portion ofthe electrode unit (explained in more detail below) and may concludethat electrode unit 104 is operating in a field-sensing non-contact modewhen the clamp portion is sufficiently proximate or a field-sensingcontact mode when the clamp portion is sufficiently far away.

It will be appreciated that the use of proximity sensors represent justone sensor-based technique for determining the operational mode of anelectrode unit 104. Sensors other than proximity sensors mayadditionally or alternatively be used to help with the determination ofthe operational mode of an electrode unit 104. For example, suitableelectrical contact sensors (e.g. micro-switches) and/or the like couldbe used to detect the presence of resistive sensor elements and/orclothing. For example, suitable proximity sensor, micro-switches,electrical contact sensors or the like could be used to detect whetheror not clamp 610 is closed and could thereby be used to determine if aresistive sensor element or clothing was being held in clamp 610.

As discussed above, electrode unit 600 comprises a capacitive sensorelement 606 which enables electrode unit 600 to operate in afield-sensing mode. FIG. 8 is an exploded cross-sectional view of acapacitive sensor element 606 that may be used with the FIG. 6A, 6Belectrode unit 600 or an electrode unit 104 according to a particularembodiment. Capacitive sensor element 606 comprises proximate and distalsurfaces 614, 620 corresponding to proximate and distal surfaces 614,620 shown in FIG. 6B. The main sensor of capacitive sensor element 606comprises an electrodynamic sensor 650 which is sensitive to localelectric field. A non-limiting example of a suitable electrodynamicsensor 650 is described, for example, in U.S. Pat. No. 7,885,700.Another non-limiting example of a suitable electrodynamic sensor 650 isthe sensor No. PS25205B marketed by Plessey Semiconductors Ltd. of theUK.

Capacitive sensor element 606 of the FIG. 8 embodiment comprises anumber of components and layers:

-   -   An antenna component 652 which serves as an antenna to increase        electromagnetic signal sensitivity of electrodynamic sensor 650        and to improve the signal resolution of electrodynamic sensor        650. Antenna component 652 of the illustrated embodiment        comprises a PCB core 654. On an inner side of PCB core 654,        antenna component 652 comprise a layer of metallization (e.g.        solder plated conductor) 656 which is in direct electrical        contact with electrodynamic sensor 650 (described below). On an        outer side of PCB core 654, antenna component 652 comprises a        layer of metallization (e.g. solder plated conductor) 658, which        is in turn coated with a thin non-conductive protective (e.g.        solder mask) layer 660. Inner and outer metallization layers        656, 658 are electrically connected to one another by conductive        vias 662 provided at suitable locations. Outer metallization        layer 658 may be transversely recessed (e.g. by 1-5 mm) at its        transverse edges 568A to insulate outer metallization layer 658        from sensor housing 659. Metallization layer 658 (and, possibly        metallization layer 656) may serve as the radiating element of        an antenna which is in electrical contact with the sensing        surface of electrodynamic sensor 650. Metallization layer 658        and, possibly metallization layer 656 (i.e. the radiating        element of antenna component 652) may have a surface area that        is greater than a surface area of the sensing surface of        electrodynamic sensor 650. In some embodiments, an outer        peripheral rim of antenna component 652 could be provided with a        stepped profile (e.g. an outer peripheral rim having less        thickness in the left-to-right dimension of FIG. 8) to        accommodate the thickness of rim 618A (see FIG. 6B).    -   A sensor-positioning layer 664 may be used on an inside of        antenna layer 652 and may provide a cut-out 666 as shown to        ensure the proper placement and/or orientation of electrodynamic        sensor 650. Sensor-positioning layer 664 may comprise a suitable        non-conductive PCB material or a single-layer PCB substrate with        etched out copper layer.    -   A sensor-holding layer 668 which holds electrodynamic sensor        650. Sensor-holding layer 668 may comprise a sensor-holding PCB.        Sensor-holding layer 668 may provide suitable solderable        contacts to solder electrodynamic sensor 650 and suitable        electrical connections to main PCB layer 672 described below. In        some embodiments, sensor-holding layer 668 and main PCB layer        672 may comprise complementary (e.g. male and female) electrical        contacts and/or connector components (not shown) that mate when        sensor element 606 is assembled.    -   An insulator layer 670, which provides compressive force and        facilitates proper electrical contact between the inner        metallization layer 656 of antenna layer 652 and electrodynamic        sensor 650. Insulation layer 670 may comprise Ethafoam™        material, for example. Insulator layer 670 may comprise a        cut-out section (not shown) which permits electrical connections        between sensor-holding layer 668 and main PCB layer 672 (as        discussed above).    -   A main PCB layer 672 which houses the electronic circuitry (e.g.        amplifiers, other signal conditioning components and/or the        like) for operation of capacitive sensing element 606. Main PCB        layer may provide electrical contact to cable 624 described with        reference to FIGS. 6A and 6B above.    -   A distal component 674 serving as distal surface 620. Distal        component 674 may comprise a metalized layer 676 which may        provide electrical noise shielding. In the illustrated        embodiment, metallization layer 676 is provided on the outside        of distal component 674. Distal component 674 may provide        suitable conduits (not shown) for electrical connection to snap        mechanism 622.    -   A snap-mechanism 622 for connecting to complementary snap        mechanism 626 of resistive sensor elements 608. In the        illustrated embodiment, snap-mechanism 622 comprises a female        snap mechanism. In other embodiments, however, snap-mechanism        622 could comprise a male snap mechanism. As discussed above,        snap-mechanism 622 may be electrically connected to a conductor        in cable 624. Snap-mechanism 622 may be electrically insulated        from metallization layer 676 by suitable etching of        metallization layer 676 or some other suitable insulating        technique.

In some embodiments, electrode unit 104 comprises capacitive sensorelement 606 as described herein to enable electrode unit 104 to operatein a field-sensing mode and may be provided with or without componentsthat permit operation in current sensing mode. In some embodiments,electrode assembly 404 comprises one or more electrode units 104 thatoperate in field-sensing mode and comprises capacitive sensor element606. In some embodiments, capacitive sensor elements 606, individually,or as part of electrode unit 104, multimode electrode unit 600 orelectrode assembly 404 may be incorporated into clothing, such asshirts, pants, shoes, clothing accessories, including watches, hats,belts, headbands, helmets, fitness bands, sports equipment, including,pads (e.g. shoulder, knee, elbow pads, and/or the like), guards, gloves,and the like. In some embodiments, capacitive sensor elements 606 may beembedded (e.g. sewn into, attached to, and/or the like) within clothing,clothing accessories, sports equipment, and the like. Capacitive sensorelements 606, electrode unit 600, and/or electrode assembly 404 may alsobe embedded or incorporated into or contained within seats (e.g. seats(operator seat(s) and/or other seat(s)) in a vehicle such as a car,plane, motorcycle, truck, boat, or the like, car seats, strollers,and/or the like), chairs (e.g. wheelchairs and/or the like), restraintsfor the seats and/or chairs (e.g. seat belts, safety belts, and/or thelike), the controls of a vehicle (e.g., in the handle bars of amotorcycle, in the steering wheel of a car, and/or the like), beds (e.g.a hospital bed, crib, bed frame, and/or the like), couches, and/or thelike, furniture (e.g. tables, sofas, recliners, and/or the like),decorations, furnishings (e.g. cushions, pillows, and/or the like), andother fixtures (e.g. toilet seats, sinks, bath tub, and/or the like). Insome embodiments, capacitive sensor elements 606, electrode unit 600,and/or electrode assembly 404 may be embedded or incorporated into orcontained within emergency response vehicles, such as police cars,ambulance, fire engines, and/or the like, and military vehicles, such astanks, armored vehicles, infantry vehicles, amphibious vehicles, troopercarriers, engineering vehicles, military aircraft and/or the like. Theseimplementations allow capacitive sensor elements 606, electrode unit600, and/or electrode assembly 404 to operate in field sensing mode andto detect electrical signals from the heart muscle of an individual orother when the individual is wearing clothing and clothing accessoriesor when the individual is in close proximity to the chairs, beds,couches, furniture, decorations, furnishings, and fixtures. In someembodiments, capacitive sensor elements 606, electrode unit 600, and/orelectrode assembly 404 may be used to sense other types ofelectrically-based physiological phenomena (physiological electricalactivity), such as electrical activity of the brain (e.g. EEG data),electrical activity associated with skeletal muscles (e.g. EMG data),electrical activity of the eye (e.g. EOG data) and/or the like. In someembodiments, electrode assembly 404 is powered by batteries, includingremovable or non-removable batteries. In some embodiments, thesebatteries are charged using a physical connection to a source ofelectricity. In other embodiments, these batteries are chargedwirelessly. In some embodiments, these batteries may be charged by bodymovement. In some embodiments, these batteries may be charged by bodyheat. In other embodiments, electrode assemblies 404 may be charged by acombination of any of the foregoing methods.

ECG systems (e.g. systems 100, 200, 300, 400) according to particularembodiments may include mechanisms for reducing the effects of ambientelectrical noise. More particular, ECG systems according to particularembodiments may comprise one or both of a grounding strap (not shown) ora right leg electrode (not shown). Such a grounding strap or right legelectrode may be used in addition to the grounding techniquesimplemented in electrode units 104 and/or in addition to filteringtechniques provided by signal processing components described above toreduce the ambient electrical noise's impact on received electricalheart activity signals. Some sources of ambient noise (e.g. power linehum that could be either 60 Hz or 50 Hz) may be too strong to beeffectively filtered by using the signal processing circuitry of the ECGsystems. Accordingly, in some embodiments, one or both of a groundingstrap or a right leg electrode may be used to increase thesignal-to-noise ratio for subsequent signal processing.

A grounding strap may be provided to link the negative side of the powersource (e.g. battery (not shown)) of base unit 102 to the individual'sskin while limiting the current flow for safety of the individual. Sucha grounding strap may be similar to the grounding straps used inelectronics laboratories and/or electronic fabrication facilities andmay be worn so as to touch the individual's skin to be effective forambient electrical noise rejection (e.g. common mode rejection of theamplifiers associated with electrode units 104).

A Right Leg Drive (RLD) electrode may be implemented to inject the“inverted” polarity noise of same amplitude as an ambient electricalnoise onto an individual's skin in order to compensate for the commonmode noise. The RLD circuitry may comprise an inverting amplifier, afilter and a safety limiting resistor to prevent exceeding the safetylimit of the noise signal injected onto the skin. This RLD electrode mayor may not touch the skin in order to inject inverted ambient noise intothe system. The DSP may use the inverted ambient noise signal from theRLD electrode to at least partially cancel ambient noise and to therebyincrease the signal-to-noise ratio. A RLD electrode may be provided withsimilar physical characteristics as electrode to unit 600 describedabove and may comprise a clamp portion similar to clamp portion 602 forattaching to an individual's clothing or the like.

In some embodiments, ECG systems 100, 200, 300, 400 (FIGS. 4A-4D) areportable and lightweight systems that are convenient to use andtransport. For example, they may be compact enough to be carried by handso that they are easy to transport to an individual's current location,which may be in the individual's home or in some other location. In someembodiments, ECG systems 100, 200, 300, 400 may be designed to be smallenough to fit within a carrying bag or pocket.

FIG. 9 illustrates an ECG system 900 incorporating a harness 901 and aplurality of electrode units 104 according to a particular embodiment.In many respects, ECG system 900 is similar to ECG systems 100, 200,300, 400 (FIGS. 4A-4D) described above. In the illustrated embodiment ofsystem 900, harness 901 comprises a rigid portion 903 one or more straps910 that wrap around the body of an individual or are otherwise shapedto fit on or to be worn around the individual's body. In someembodiments, straps 910 are configured to extend from and recoil intorigid components 903, which may be located at the front of theindividual's body (as illustrated in FIG. 9) and/or located at the backand/or to the side of the individual's body. Harness 901 and/or straps910 may comprise components that are connected to each other byfasteners, such as hook and loop, clips, buttons, and/or the like.Electrode units 104 may be similar to electrode units 104 describedelsewhere herein and may comprise any feature(s) of and/ormodification(s) to electrode units 104. In some embodiments, electrodeunits 104 may comprise capacitive sensor elements, each having anelectrodynamic sensor sensitive to electromagnetic waves and an antennacomprising an electrically conducting radiating element for receivingelectromagnetic waves as described elsewhere herein. In someembodiments, electrode units may comprise multi-mode electrode units 600of the type described herein. In the FIG. 9 embodiment, electrode units104 are provided as part of electrode assemblies 404 which may besubstantially similar to electrode assemblies 404 described elsewhereherein and may comprise any feature(s) of or modification(s) toelectrode assemblies 404. Electrode assemblies 404 may be located atlocations (e.g. adjustable locations) on harness 901 and/or straps 910so that when harness 901 is worn by an individual, electrode assemblies404 will be located in desirable positions relative to the heart—e.g.for detection of suitable ECG data. Electrode assemblies 404 may beintegrated into or embedded within harness 901 and/or straps 910 orattached to harness 901 and/or straps 910 by hooks, clips, compressionclips, hook and loop systems, and the like. In some embodiments, harness901 comprises tracks such that electrode assemblies 404 are movablealong the tracks to different locations of the person's body. In someembodiments, harness 901 comprises location indicators, such as acoloured indicator, an identification spot, and/or the like, to allowthe wearer to position electrode assembles 404 to the applicablelocation on the wearer's body. In other embodiments, harness 901comprises measurement lines, a ruler, and/or the like to allow thewearer to measure distances between locations on harness 901. Thelocation indicators and/or measurement lines may also allow differentwearers to adjust the locations of electrode assemblies 404 on harness901 depending on the wearer's body type and/or body traits. System 900may comprise controls for operating electrode assemblies 404, such ascontrols for switching individual electrode units 104 betweenfield-sensing and current-sensing modes (e.g. where electrode units 104comprise multi-mode electrode units, such as electrode units 600),on-off switches, and the like. In some embodiments, harness 901comprises compression clamps, and the compression clamps hold electrodeassemblies 404 at appropriate locations on an individual's body. In someembodiments, electrode assembly 404 or electrode unit 104 comprisescapacitive sensor element having an electrodynamic sensor sensitive toelectromagnetic waves and an antenna comprising an electricallyconducting radiating element for receiving electromagnetic waves asdescribed elsewhere herein.

System 900 may also comprise a base unit 920 which may be similar tobase unit 402 of ECG system 400 described above. Base unit 920 maycomprise suitable communication hardware (not shown) similar tocommunication hardware 430 described above, which may facilitatecommunication between electrode assemblies 404 and external ECG systemsor to other devices (not shown) such as a smartphone, tablet, laptop,computers, and/or the like. Communication between electrode units 104and base unit 920 may be by wire or cable embedded within or attached toharness 901, straps 910, tracks, and/or the like. Communication betweenelectrode units 104 and base unit 920 may additionally or alternativelybe wireless according to any suitable wireless communication protocol.Communication between base unit 920 and the external ECG system and/orother devices may be wireless according to any suitable wirelesscommunication protocol. Base unit 920 may comprise connectivityindicators 922 to allow the harness wearer to determine whether reliablecommunication is established between base unit 920 and the external ECGsystem and/or other devices. System 900 may also incorporate othersensors or medical devices such as blood pressure cuff, pulse oximeters,glucose monitors, and/or the like, although this is not necessary.

Electrode units 104 described herein (including electrode units 204,304, 600 and electrode assemblies 404) are sensitive to electricalcharacteristics of the body (physiological electrical activity), whetherthey are current-sensing electrode units, field-sensing electrode units,multi-mode electrode units operating in current-sensing mode ormulti-mode electrode units operating in contact or non-contactfield-sensing mode. Because of this sensitivity to physiologicalelectrical activity, electrode units 104 may be used to sensephysiological electrical activity other than the electrical activity ofthe heart muscle and can be used as a part of corresponding systems usedto generate other types of data based on such physiological electricalactivity (e.g. electrical characteristics of other cell(s), tissue(s),organ(s) and/or system(s) in the person's body). By way of non-limitingexample, electrode units similar in many respects to electrode units 104described herein could be used to sense other types ofelectrically-based physiological phenomena (physiological electricalactivity), such as electrical activity of the brain (e.g. as part of anEEG system for generating EEG data), electrical activity associated withskeletal muscles (e.g. as part of an EMG system for generating EMGdata), electrical activity of the eye (e.g. as part of an EOG system forgenerating EOG data) and/or the like. Using such electrode units, ECGsystems 100, 200, 300, 400, and/or 900 described herein could be used orsuitably modified for use as EEG, EMG and/or EOG systems. Similarly,signal processing systems 500A, 500B could be used or suitably modifiedfor use in EEG, EMG and/or EOG systems.

FIG. 10 schematically illustrates an EEG system 1000 according to aparticular embodiment. EEG system 1000 of the FIG. 10 embodiment isshown having a general architecture that is similar to ECG system 400(FIG. 4D) and similar reference numerals are used to refer to featuresof EEG system 1000 that are similar to corresponding features of ECGsystem 400. It will be appreciated by those skilled in the art (giventhe description of ECG systems 100, 200, 300, 400 above and thedescription of EEG system 1000 below) that EEG system 1000 could bemodified to have the general architecture of any of ECG systems 100,200, 300, and 400. EEG system 1000 comprises a base unit 1002 and two ormore electrode assemblies 1004A, 1004B, 1004C (collectively andindividually electrode assemblies 1004). Consistent with thearchitecture of ECG system 400 (FIG. 4D), each electrode assembly 1004of the illustrated embodiment of EEG system 1000 comprises acorresponding electrode unit 104A, 104B, 104C which may be similar toelectrode units 104 described herein, but which may be configured fordetection of brain activity and corresponding EEG data. By way ofnon-limiting example, electrode units 104 may comprise multi-modeelectrode units similar to multi-mode electrode units 600 describedherein. In some embodiments, electrode units 600 comprise capacitivesensor element 606 and the capacitive sensor element 606 comprisesantenna component 652 and electrodynamic sensor 650 as described herein.In some embodiments, electrode units 104 may comprise one or morecapacitive sensor elements, each having an electrodynamic sensorsensitive to electromagnetic waves and an antenna comprising anelectrically conducting radiating element for receiving electromagneticwaves as described elsewhere herein.

Consistent with the architecture of ECG system 400 (FIG. 4D), eachelectrode assembly 1004 of the illustrated embodiment of EEG system 1000comprises corresponding signal processing components 1006A, 1006B, 1006C(collectively and individually signal processing components 1006) andcommunications components 1008A, 1008B, 1008C (collectively andindividually communications components 1008). Signal processingcomponents 1006 and communications components 1008 may be similar tosignal processing components 406 and communications components 408described herein, but may be configured for detection of brain activityand corresponding EEG data. In some embodiments, signal processingcomponents 1006 (and/or signal processing components 114 of base unit1002) comprise signal amplifiers with very low noise. The input signalsbeing measured by electrode units 104 in electrode assemblies 1004 ofEEG system 1000 may be as low as tens of microvolts peak-to-peak;accordingly, amplifiers having noise levels below this may be desirable.Electrode units 104 and/or electrode assemblies 1004 may detectelectrical signals from the brain in current-sensing mode, field-sensingcontact mode and/or field sensing non-contact mode. In one embodiment,one electrode unit 104 and/or electrode assembly 1004 detects electricalsignals from the brain in current-sensing mode with the other electrodeunit 104 and/or electrode assembly 1004 in field-sensing contact mode orfield sensing non-contact mode. In other embodiments, electrode units104 and/or electrode assemblies 1004 may all operate in field-sensingnon-contact mode to detect electrical signals from the brain. In someembodiments, electrode units 104 and/or electrode assemblies 1004 mayoperate in a combination of field-sensing contact mode and field-sensingnon-contact mode. In some embodiments, electrode units 104 and/orelectrode assemblies 1004 may comprise one or more capacitive electrodesensor elements, each having an electrodynamic sensor sensitive toelectromagnetic waves and an antenna comprising an electricallyconducting radiating element for receiving electromagnetic waves asdescribed elsewhere herein.

Base unit 1002 may be positioned at a location 105 away from anindividual's body 101 and electrode assemblies 1004 may communicatemeasured signals or data back to base unit 1002. In some embodiments,electrode assemblies 1004 may be electrically connected to one another(e.g. to provide a common ground or reference potential). In someembodiments, electrode assemblies 1004 may share some of signalprocessing components 1006 and/or communications components 1008. Insome embodiments, electrode assemblies 1004 may comprise suitablyconfigured controllers (not shown) which may control signal processingcomponents 1006 and/or communications components 1008. In the embodimentillustrated in FIG. 10, electrode assemblies 1004 communicate wirelesslyto base unit 1002. In some embodiments, one or more than one ofelectrode assemblies 1004 may be physically connected to base unit 1002by corresponding cables and may communicate to base unit 1002 throughsuch cables. In some embodiments, electrode assemblies 1004 may bephysically connected to a signal transmitter by a wire harness, and thesignal transmitter communicates signals from electrode assemblies 1004to base unit 1002 wirelessly. In some embodiments, electrode assemblies1004 are similar to electrode units 104 in FIG. 4A whereby electrodeassemblies 1004 may be removably connected to base unit 1002 usingsuitable electrical, signal transmission connectors, which may compriseslidable locking electric connectors, spring-biased electric connectors,magnetic connectors and/or the like.

Electrode assemblies 1004 may be located relative to a subject's body101 (e.g. around a person's head in a hat, a net and/or the like,embedded within, or attached to the inside of, a hat, cap, helmet,and/or the like (including the pad material, if any, inside any of theforegoing)) to generate signals indicative of electrical activity of thesubject's brain at their corresponding locations and may wirelesslycommunicate these signals back to base unit 1002 at a location 105 awayfrom the subject's body 101. While electrical potentials of individualneurons in the brain may be too small to detect reliably, electrodeassemblies 1004 and EEG system 1000 may detect activity of groups ofneurons having similar spatial orientations. In the illustratedembodiment of FIG. 10, EEG system 1000 is shown as having threeelectrode assemblies 1004A, 1004B, 1004C which may be used in a suitableconfiguration for generating EEG data. In some embodiments, thirdelectrode assembly 1004C is not necessary and system 1000 may use as fewas two electrode assemblies 1004. In some embodiments, system 1000 maybe provided with more than three electrode assemblies 1004 (e.g. tens oreven hundreds of electrode assemblies 1004) to provide additional viewsof brain electrical activity

Base unit 1002 of EEG system 1000 and display 120 may be similar in manyrespects to base unit 402 of ECG system 400 and display 120 of ECGsystem 400 described herein. EEG waveforms 1010 generated by EEG system1000 based on signals received from electrode assemblies 1004 may beshown on display 120 and display 120 may be mounted in cradle 122 orremoved from base unit 1002. Base unit 1002 may comprise suitablyconfigured hardware and/or software components for processing signalsfrom electrode assemblies 1004 and for generating corresponding EEGwaveforms. In the illustrated embodiment of FIG. 10, base unit 1002 ofEEG system 1000 comprises: controller 112, signal processing hardware114, data storage 116, communications hardware 130 and user interfacecomponents 132. These components may be configured to provide particularfunctionality using suitably coded software (not explicitly shown). Insome embodiments, communications hardware 130 may facilitatecommunication of EEG data (e.g. data stored in data storage 116, realtime EEG waveforms 1010 and/or the like) from base unit 102 to anexternal EEG system 1024. Other than for dealing with EEG data (inaddition to or in the alternative to ECG data) and possibly for dealingwith external EEG system(s) 1024, these components of EEG system 1000may be similar to the corresponding components of ECG system 400described above. Base unit 1002 may comprise additional connectors 108for optional connection to additional or alternative electrode units(not shown); and/or connections 134 for connecting to other medicalequipment. Connectors 108 and connections 134 may be similar to thosedescribed above for ECG system 400.

In some embodiments, electrode units 104 and/or electrode assemblies1004 are embedded into, contained within, or attached to the inside ofhelmets, such as firefighter helmets, athlete helmets, soldier helmets,and the like (including the padding, such as foam, containedtherewithin). In these embodiments, EEG system 1000 may be used tomonitor the electrical activity of the brain of the individual wearingthe helmets, such as firefighters, athletes, soldiers, and the like. Thebrain activity as shown in the form of EEG waveforms 1010 may be used toassess the condition of the helmet-wearing individual to determinewhether the individual is in the proper condition for performing thespecific tasks.

In some embodiments, electrode units 104 and/or electrode assemblies1004 are fixed on the head of an individual corresponding to thelocations known as the 10-20 international system of EEG electrodeplacement. In some embodiments, electrode units 104 and/or electrodeassemblies 1004 are held to the skin of the individual through fastenerssuch as tape, adhesives, clips, elastic strap(s) and/or the like. Insome embodiments, electrode assemblies 1004 are held in place on oraround a subject's head through the use of compression clamps. In someembodiments, electrode units 104 and/or electrode assemblies are not incontact with the skin of the individual. Electrode units 104 and/orelectrode assemblies 1004 may additionally or alternatively be heldusing a holder arm firmly fixed to an individual's bed, chair, seat orother furniture around the individual. Electrode units 104 and/orelectrode assemblies 1004 may additionally or alternatively be held inpockets of hats or in suitable netting. Such hats or netting may beelastically deformable to deform when a person's head is insertedtherein, such that restorative forces associated with such deformationtend to hold the hat (and the corresponding electrode units 104 and/orelectrode assemblies 1004) to the person's head in the correct locationsdesired for monitoring. In some embodiments, snap connectors may be usedto hold such hats or netting in place.

Electrode units 104 or electrode assemblies 1004, may also be used,whether as part of a helmet, hat, headband, or other types of headgearon individuals, to allow doctors to monitor whether the individual issuffering from brain conditions, such as strokes, seizures, hemorrhages,and the like. In some embodiments, EEG system 1000 comprises alarmswhich are sounded when EEG system 1000, after analyzing EEG waveforms1010, determines that the individual is having trauma or some otherdetectable condition in the brain. In some embodiments, EEG system 1000communicates EEG waveforms 1010 to a computing device (e.g. device 126A)that is operated by, or a display shown to, a doctor, technician, or thelike, both of which allow the doctor, the technician, or the like toremotely monitor the brain activities of an individual. EEG system 1000may be incorporated into medical diagnostic equipment, neuroprosthesesor systems for use in detecting biofeedback, neuroimaging,brain-computer interfaces, interactive computer games, and the like. Insome embodiments, EEG system 1000 can also be used to detect hearing ininfants.

In some embodiments, EEG system 1000 may be installed in vehicles, suchas cars, trucks, buses, planes, trains, and the like. Electrode units104 and/or electrode assemblies 1004 may be installed or embedded intoor contained within the interior of the vehicle, such as the steeringwheel, seats (e.g. operator seat(s) and/or other seat(s)), headrests,dashboard, seat restraints (such as seat belts, safety belts, and/or thelike), ceiling panel, ground panel, side panel, and/or the like. Baseunit 1002 may be installed as part of the dashboard and/or control panelof the vehicle or be located in any other locations in the vehicle, suchas the trunk or other storage space of the vehicle. In suchinstallations, EEG system 1000 may or may not comprise display 120 ordisplay 102 may comprise a part of the dashboard of the vehicle, thecontrol panel of the vehicle, the entertainment system of the vehicle,heads-up display of the vehicle, or pop-up display in the vehicle.

In some embodiments, EEG waveforms 1010 may be analyzed by EEG system1000 to assess the brain of a vehicle operator to determine whether theoperator is suffering from a medical condition, is falling asleep, isdrowsy, is driving under the influence of drugs, alcohol, or the like,or is otherwise impaired or unable to operate the vehicle appropriately.In some embodiments, EEG system 1000 is configured to send a distresssignal, distress call, or warning signal to emergency responders, suchas firefighters, police, and the like, emergency dispatch centers, orin-vehicle telematics service providers, when the brain of a vehicleoperator is being affected by adverse medical conditions, trauma, or thelike or when an accident has occurred, including accidents where one ormore airbags have been activated. EEG system 1000 may contact emergencyresponders and emergency dispatch center through communication hardware130, including through wireless communication modules. EEG system 1000may also communicate EEG waveforms 1010 to emergency responders andmedical personnel or allow data containing information about the EEGwaveforms 1010 to be accessed and/or downloaded by emergency respondersor medical personnel to assist the responders and medical personnel indiagnosing and treating the vehicle operator. In some embodiments, EEGsystem 1000 may interface or communicate with a vehicle's safetysystems, such as active cruise control system, lane departure warningsystem, frontal collision warning system, precrash system, collisionmitigating system, collision avoidance system, and/or the like to reducethe likelihood of an accident occurring while the vehicle operator isincapacitated or otherwise unable to operate the vehicle.

In one embodiment, EEG system 1000 is operatively connected to thevehicle's embedded software system such that EEG system 1000 cancommunicate with the vehicle's systems to effect changes in thevehicle's physical parts, such as the brakes, engine, and the like. Whena vehicle operator steps into the vehicle (e.g. possibly, but notnecessarily before starting the vehicle), a vehicle operator may beasked to place one electrode unit 104 and/or one electrode assembly 1004onto the vehicle operator's head (operating in a current sensing mode ora contact field-sensing mode, in some embodiments) and one or moreelectrode units 104 and/or electrode assemblies 1004 embedded in thehead rest of the vehicle operator's seat (operating in a non-contactfield sensing mode, in some embodiments). It will be appreciated that,in some embodiments, additional or alternative locations of electrodeunits 104 and/or electrode assemblies 1004 could be used and that suchelectrode units (depending on their locations) could operate incurrent-sensing mode, field-sensing contact mode or field sensingnon-contact mode. Signals detected by electrode units 104 and/orelectrode assemblies 1004 may be used to generate corresponding EEGsignals (e.g. EEG waveforms 1010), which may be analyzed (e.g. bycontroller 112, other controllers in EEG system 1000, or external EEGsystems 1024 (communicating with EEG system 1000 through communicationscomponent 1024A)) to determine the state of the vehicle operator'sbrain. The analysis may be done through the use of software algorithmsand may include comparison to other data sets. Where the EEG waveforms1010 indicate the individual is incapacitated or is not in the propercondition to operate the vehicle, controller 112 communicates with thevehicle's on board system, which may act in accordance with instructionsfrom controller 112. In some embodiment, if the EEG waveform 1010indicates that the vehicle operator is going to fall asleep, is drowsy,or is already asleep, controller 112 communicates an alarm instructionto the vehicle system, and the vehicle system, upon receiving theinstruction, will sound an alarm insider the vehicle or increase thevolume of the radio and/or music playing in the entertainment system towake the vehicle operator. In some embodiments, the alarm may be avibration of the operator's seat to wake the vehicle operator. Infurther embodiments, the vehicle's infotainment system may ask thevehicle operator questions or require the vehicle operator to issuecommands in order to wake, keep awake or otherwise maintain thealertness of the vehicle operator. In another embodiment, if the EEGwaveform 1010 indicates that the vehicle operator is incapacitated,controller 112 will not permit the vehicle to start or will communicatea stop instruction to the vehicle's system, and the vehicle's systemwill turn on the vehicle's emergency stop lights and slowly brake thevehicle to a stop. EEG system 1000 may also communicate the vehicleoperator's location and condition to emergency dispatchers such thatemergency personnel can attend to the vehicle's vehicle operatorquickly. Data from such vehicular EEG systems may be recorded—e.g. forforensic analysis, data analytics and/or the like.

FIG. 11 schematically illustrates an EMG system 1100 according to aparticular embodiment. EMG system 1100 of the FIG. 11 embodiment isshown having a general architecture that is similar to ECG system 400(FIG. 4D) and similar reference numerals are used to refer to featuresof EMG system 1100 that are similar to corresponding features of ECGsystem 400. It will be appreciated by those skilled in the art (giventhe description of ECG systems 100, 200, 300, 400 above and thedescription of EMG system 1100 below) that EMG system 1100 could bemodified to have the general architecture of any of ECG systems 100,200, 300, and 400. EMG system 1100 comprises a base unit 1102 and two ormore electrode assemblies 1104A, 1104B, 1104C (collectively andindividually electrode assemblies 1104). Consistent with thearchitecture of ECG system 400 (FIG. 4D), each electrode assembly 1104of the illustrated embodiment of EMG system 1100 comprises acorresponding electrode unit 104A, 104B, 104C which may be similar toelectrode units 104 described herein, but which may be configured fordetection of skeletal muscle activity and corresponding EMG data. Insome embodiments, electrode units 104 or electrode assemblies 1104 maycomprise one or more capacitive sensor elements, each having anelectrodynamic sensor sensitive to electromagnetic waves and an antennacomprising an electrically conducting radiating element for receivingelectromagnetic waves as described elsewhere herein. By way ofnon-limiting example, electrode units 104 may comprise multi-modeelectrode units similar to multi-mode electrode units 600 describedherein. In some embodiments, electrode units 600 comprise capacitivesensor element 606 and the capacitive sensor element 606 comprisesantenna component 652 and electrodynamic sensor 650 as described herein.

Consistent with the architecture of ECG system 400 (FIG. 4D), eachelectrode assembly 1104 of the illustrated embodiment of EMG system 1100comprises corresponding signal processing components 1106A, 1106B, 1106C(collectively and individually signal processing components 1106) andcommunications components 1108A, 1108B, 1108C (collectively andindividually communications components 1108). Signal processingcomponents 1106 and communications components 1108 may be similar tosignal processing components 406 and communications components 408described herein, but may be configured for detection of skeletal muscleactivity and corresponding EMG data.

Base unit 1102 may be positioned at a location 105 away from theindividual's body 101 and electrode assemblies 1104 may communicatemeasured signals or data back to base unit 1102. In some embodiments,electrode assemblies 1104 may be electrically connected to one another(e.g. to provide a common ground or reference potential). In someembodiments, electrode assemblies 1104 may share some of signalprocessing components 1106 and/or communications components 1108. Insome embodiments, electrode assemblies 1104 may comprise suitablyconfigured controllers (not shown) which may control signal processingcomponents 1106 and/or communications components 1108.

Electrode assemblies 1104 may be located relative to an individual'sbody 101 (e.g. in suitable locations relative to specific muscles and/orthe like) to generate signals indicative of electrical activity of anindividual's skeletal muscle at their corresponding locations and maywirelessly communicate these signals back to base unit 1102 at alocation 105 away from the individual's body 101. In the illustratedembodiment of FIG. 11, EMG system 1100 is shown as having threeelectrode assemblies 1104A, 1104B, 1104C which may be used in a suitableconfiguration for generating EMG data. In some embodiments, thirdelectrode assembly 1104C is not necessary and system 1100 may use as fewas two electrode assemblies 1104. In some embodiments, system 1100 maybe provided with more than three electrode assemblies 1104 to provideadditional views of skeletal muscle electrical activity. Electrode units104 and/or electrode assemblies 1104 may detect electrical signals fromthe skeletal muscles in current-sensing mode, field-sensing contact modeand/or field sensing non-contact mode. In one embodiment, one electrodeunit 104 and/or electrode assembly 1104 detects electrical signals froma skeletal muscle in current-sensing mode with the other electrode unit104 and/or electrode assembly 1104 in field-sensing contact mode orfield sensing non-contact mode. In other embodiments, electrode units104 and/or electrode assemblies 1104 may all operate in field-sensingnon-contact mode to detect electrical signals from the skeletal muscle.In some embodiments, electrode units 104 and/or electrode assemblies1104 may operate in a combination of field-sensing contact mode andfield-sensing non-contact mode.

Base unit 1102 of EMG system 1100 and display 120 may be similar in manyrespects to base unit 402 of ECG system 400 and display 120 of ECGsystem 400 described herein. EMG waveforms 1110 generated by EMG system1100 based on signals received from electrode assemblies 1104 may beshown on display 120 and display 120 may be mounted in cradle 122 orremoved from base unit 1102. Base unit 1102 may comprise suitablyconfigured hardware and/or software components for processing signalsfrom electrode assemblies 1104 and for generating corresponding EMGwaveforms. In the illustrated embodiment of the FIG. 11 EMG system 1100,base unit 1102 comprises: controller 112, signal processing hardware114, data storage 116, communications hardware 130 and user interfacecomponents 132. These components may be configured to provide particularfunctionality using suitably coded software (not explicitly shown). Insome embodiments, communications hardware 130 may facilitatecommunication of EMG data (e.g. data stored in data storage 116, realtime EMG waveforms 1110 and/or the like) from base unit 102 to anexternal EMG system 1124. Other than for dealing with EMG data (inaddition to or in the alternative to ECG data) and possibly for dealingwith external EMG system(s) 1124, these components of EMG system 1100may be similar to the corresponding components of ECG system 400described above. Base unit 1102 may comprise additional connectors 108for optional connection to additional or alternative electrode units(not shown); and/or connections 134 for connecting to other medicalequipment. Connectors 108 and connections 134 may be similar to thosedescribed above for ECG system 400. In the embodiment illustrated inFIG. 11, electrode assemblies 1104 communicate wirelessly to base unit1102. In some embodiments, one or more than one of electrode assemblies1104 may be physically connected to base unit 1102 by correspondingcables and may communicate to base unit 102 through such cables. In someembodiments, electrode assemblies 1104 may be physically connected to asignal transmitter by a wire harness, and the signal transmittercommunicates signals from electrode assemblies 1104 to base unit 1102wirelessly. In some embodiments, electrode assemblies 1104 are similarto electrode units 104 in FIG. 4A whereby electrode assemblies 1104 maybe removably connected to base unit 1102 using suitable electrical,signal transmission connectors, which may comprise slidable lockingelectric connectors, spring-biased electric connectors, magneticconnectors and/or the like.

In some embodiments, electrode assemblies 1104 are in direct contactwith the skin of an individual. In other embodiments, electrodeassemblies 1104 are not in contact with the skin of an individual. Inone embodiment, electrode assemblies 1104 are mounted on an individual'sbody using a stretch band stretching around a limb with the band eitherendless or with the ends of the band fixed together by fasteners such ashook and loop fasteners, pins, buckles, and the like. In someembodiment, electrode assemblies 1104 are embedded into, containedwithin, incorporated into, or attached to sports equipment, such asfitness bands, shin pad, shin guard, knee pad, elbow pad, arm pad,shoulder pad, leg guard, chest protector, body pad, wrist pad, glove,and/or the like. In some embodiments, electrode assemblies 1104 are heldin place on or around specific muscles through the use of compressionclamps.

EMG system 1100 may also be used to monitor the activity of specificskeletal muscles of individuals, such as patients, athletes, soldiers,and the like. EMG waveforms 1110 may further be used to diagnose and/orassessing neuromuscular disease, back pain, motor control disorder,neuropathies, neuromuscular junction diseases, myopathies and/or thelike. EMG signals detected by EMG system 1100 may also be used ascontrol signals for prosthetic devices such as prosthetic hands, arms,lower limbs, and the like. EMG signals may further be used to assessstrength, condition, and fatigue levels of specific muscles.

In one embodiment, an athlete wears a pad (e.g. a shin guard and/or thelike) that incorporates two or more electrode assemblies 1104. Oneelectrode assembly 1104 directly contacts the skin of the individual andoperates in current sensing mode and/or field sensing contact mode. Theother electrode assembly 1104 is not in direct contact with the skin andoperates in field sensing non-contact mode. In some embodiments, bothelectrode assemblies 1104 operate in field sensing non-contact mode. Itwill be appreciated that, in some embodiments, additional or alternativelocations of electrode units 104 and/or electrode assemblies 1104 couldbe used and that such electrode units (depending on their locations)could operate in current-sensing mode, field-sensing contact mode orfield sensing non-contact mode. EMG waveforms 1110 are then analyzed bycontroller 112, other controllers in EMG system 1100, or external EMGsystem 1124 (which may be in communication with base unit 1102 throughexternal EMG communication component 1124A) through the use of softwarealgorithms. EMG waveforms 1110 may also be shown on display 120 in EMGsystem 1100 and analyzed by technicians, physicians, coaches, theathlete himself or herself, and the like. EMG waveforms 1100 may be usedto determine the state of an individual's skeletal muscle (e.g. themuscle(s) under the athlete's pad), such as the tibialis anteriormuscle. Such analysis of skeletal muscle activity can be used toascertain muscle fatigue, muscle damage, muscle strength, musclecondition and/or the like.

In some embodiments, EMG system 1100 may be installed in vehicles, suchas cars, trucks, busses, planes, trains, and the like. Electrode units104 and/or electrode assemblies 1104 may be installed or embedded intoor contained within the interior of the vehicle, such as the seats, armrests, seat restraints, and/or the like. In some embodiments EMG system1100 is used with adjustable seat systems, such as adjustable seats invehicles, office chairs, massage chairs, and/or the like. EMG system1100 uses EMG waveforms 1110 to determine the strain in of skeletalmuscles of an individual sitting in the seats. EMG system 1100 may thencommunicate with the controller of the adjustable seat systems to adjustthe characteristics of the seats, such as curvature, height, tilt,and/or the like, to reduce the strain in the individual's skeletalmuscles. In some embodiments, EMG system 1100 may interface orcommunicate with a vehicle's safety systems, such as active cruisecontrol system, lane departure warning system, frontal collision warningsystem, precrash system, collision mitigating system, collisionavoidance system, and/or the like to reduce the likelihood of anaccident occurring while the vehicle operator is incapacitated orotherwise unable to operate the vehicle.

In some embodiments, EMG system 1100 is used as part of a human-machineinterface in which EMG signals and EMG waveforms 1110 are used fordetecting the motion of an individual. Such detection can then be usedfor interpreting gestures performed by the individual. In someembodiments, EMG system 1100 is incorporated into medical diagnosticequipment or neuroprostheses.

FIG. 12 schematically illustrates an EOG system 1200 according to aparticular embodiment. EOG system 1200 of the FIG. 12 embodiment isshown having a general architecture that is similar to ECG system 400(FIG. 4D) and similar reference numerals are used to refer to featuresof EOG system 1200 that are similar to corresponding features of ECGsystem 400. It will be appreciated by those skilled in the art (giventhe description of ECG systems 100, 200, 300, 400 above and thedescription of EOG system 1200 below) that EOG system 1200 could bemodified to have the general architecture of any of ECG systems 100,200, 300, and 400. EOG system 1200 comprises a base unit 1202 and two ormore electrode assemblies 1204A, 1204B, 1204C (collectively andindividually electrode assemblies 1204). Consistent with thearchitecture of ECG system 400 (FIG. 4D), each electrode assembly 1204of the illustrated embodiment of EOG system 1200 comprises acorresponding electrode unit 104A, 104B, 104C which may be similar toelectrode units 104 described herein, but which may be configured fordetection of corneo-retinal potential and corresponding EOG data. Insome embodiments, electrode units 104 or electrode assemblies 1204 maycomprise one or more capacitive sensor elements, each having anelectrodynamic sensor sensitive to electromagnetic waves and an antennacomprising an electrically conducting radiating element for receivingelectromagnetic waves as described elsewhere herein. By way ofnon-limiting example, electrode units 104 may comprise multi-modeelectrode units similar to multi-mode electrode units 600 describedherein. In some embodiments, electrode units 600 comprise capacitivesensor element 606 and the capacitive sensor element 606 comprisesantenna component 652 and electrodynamic sensor 650 as described herein.

Consistent with the architecture of ECG system 400 (FIG. 4D), eachelectrode assembly 1204 of the illustrated embodiment of EOG system 1200comprises corresponding signal processing components 1206A, 1206B, 1206C(collectively and individually signal processing components 1206) andcommunications components 1208A, 1208B, 1208C (collectively andindividually communications components 1208). Signal processingcomponents 1206 and communications components 1208 may be similar tosignal processing components 406 and communications components 408described herein, but may be configured for detection of electricalactivity of the eye and corresponding EOG data.

Base unit 1202 may be positioned at a location 105 away from theindividual's body 101 and electrode assemblies 1204 may communicatemeasured signals or data back to base unit 1202. In some embodiments,electrode assemblies 1204 may be electrically connected to one another(e.g. to provide a common ground or reference potential). In someembodiments, electrode assemblies 1204 may share some of signalprocessing components 1206 and/or communications components 1208. Insome embodiments, electrode assemblies 1204 may comprise suitablyconfigured controllers (not shown) which may control signal processingcomponents 1206 and/or communications components 1208.

Electrode assemblies 1204 may be located relative to an individual'sbody 101 (e.g. in suitable locations relative to the individual's eye)to generate signals indicative of electrical activity of theindividual's eye at their corresponding locations and may wirelesslycommunicate these signals back to base unit 1202 at a location 105 awayfrom the individual's body 101. In the illustrated embodiment of FIG.12, EOG system 1200 is shown as having three electrode assemblies 1204A,1204B, 1204C which may be used in a suitable configuration forgenerating EOG data. In some embodiments, third electrode assembly 1204Cis not necessary and system 1200 may use as few as two electrodeassemblies 1204. In some embodiments, system 1200 may be provided withmore than three electrode assemblies 1204 to provide additional views ofcorneo-retinal electrical activity. Electrode assemblies 1204 may detectcorneo-retinal electrical activity in current-sensing mode,field-sensing contact mode and/or field sensing non-contact mode. In oneembodiment, electrode assembly 1204A detects electrical signals from thebrain in current-sensing mode with the other electrode assembly 1204 infield-sensing contact mode or field sensing non-contact mode. In otherembodiments, electrode assemblies 1204 may all operate in field-sensingnon-contact mode to detect electrical signals from the brain. In someembodiments, electrode assemblies 1204 may operate in a combination offield-sensing contact mode and field-sensing non-contact mode.

Base unit 1202 of EOG system 1200 and display 120 may be similar in manyrespects to base unit 402 of ECG system 400 and display 120 of ECGsystem 400 described herein. EOG waveforms 1210 generated by EOG system1200 based on signals received from electrode assemblies 1204 may beshown on display 120 and display 120 may be mounted in cradle 122 orremoved from base unit 1202. Base unit 1202 may comprise suitablyconfigured hardware and/or software components for processing signalsfrom electrode assemblies 1204 and for generating corresponding EOGwaveforms. In the illustrated embodiment of the FIG. 12, EOG system1200, base unit 1202 comprises: controller 112, signal processinghardware 114, data storage 116, communications hardware 130 and userinterface components 132. These components may be configured to provideparticular functionality using suitably coded software (not explicitlyshown). In some embodiments, communications hardware 130 may facilitatecommunication of EOG data (e.g. data stored in data storage 116, realtime EOG waveforms 1210 and/or the like) from base unit 102 to anexternal EOG system 1224. Other than for dealing with EOG data (inaddition to or in the alternative to ECG data) and possibly for dealingwith external EOG system(s) 1224, these components of EOG system 1200may be similar to the corresponding components of ECG system 400described above. Base unit 1202 may comprise additional connectors 108for optional connection to additional or alternative electrode units(not shown); and/or connections 134 for connecting to other medicalequipment. Connectors 108 and connections 134 may be similar to thosedescribed above for ECG system 400. In the embodiment illustrated inFIG. 12, electrode assemblies 1204 communicate wirelessly to base unit1202. In some embodiments, one or more than one of electrode assemblies1004 may be physically connected to base unit 1202 by correspondingcables and may communicate to base unit 1202 through such cables. Insome embodiments, electrode assemblies 1204 may be physically connectedto a signal transmitter by a wire harness, and the signal transmittercommunicates signals from electrode assemblies 1204 to base unit 1202wirelessly. In some embodiments, electrode assemblies 1204 are similarto electrode units 104 in FIG. 4A whereby electrode assemblies 1204 maybe removably connected to base unit 1202 using suitable electrical,signal transmission connectors, which may comprise slidable lockingelectric connectors, spring-biased electric connectors, magneticconnectors and/or the like.

In some embodiments, a pair of electrode assemblies 1204 is placed aboveand below the eye. In other embodiments, the pair of electrodeassemblies 1204 is placed to the left and right of the eye. In someembodiments, electrode assemblies 1204 are embedded into, containedwithin, incorporated into, or attached to a frame, glasses, goggles, andthe like. Signals detected by EOG system 1200 and/or EOG waveforms 1210may be used to diagnose opthalmological conditions such as Best'sdisease, macular dystrophy, retinitis pigmentosa, other retinalconditions and/or the like. In one embodiment, one of the electrodeassemblies 1204 is in direct contact with the skin around the eye andthe other electrode assembly 1204 is not in direct contact with theskin. In other embodiments, the electrode assemblies 1204 are both notin direct contact with the skin. In some embodiments, electrodeassemblies 1204 are held in place on or around a subject's eyes throughthe use of compression clamps.

In some embodiments, EOG system 1200 is used to track eye movement ofthe individual. In some embodiments, EOG system 1200 is used to trackthe eye movement for actors who are performing motion capture foranimated films. In some embodiments, EOG system 1200 may be used byindividuals giving presentations. In some embodiments, EOG system 1200may be used with entertainment systems, such as televisions, movietheatres, game consoles, and/or the like to track eye movement of theindividual.

In some embodiments, EOG system 1200 may be used as part of a vehiclesafety system. As an example, before operating a vehicle, the vehicleoperator may be to first wear a frame around the operator's face withelectrode assemblies 1204 mounted on the frame such that one of theelectrode assemblies 1204 will be in contact with the skin of thevehicle operator near one of the eyes. The electrode assembly 1204 incontact with the skin may operate in current sensing mode and/orfield-sensing contact mode and the other electrode unit 1204 on theframe may operate in field sensing non-contact mode. In otherembodiments, electrode assemblies 1204 are located near the eye but notin contact with the skin of the vehicle operator. It will be appreciatedthat, in some embodiments, additional or alternative locations ofelectrode units 104 and/or electrode assemblies 1204 could be used andthat such electrode units (depending on their locations) could operatein current-sensing mode, field-sensing contact mode or field sensingnon-contact mode. Signals detected from electrode assemblies 1204 aresent to signal processing system 114 in base unit 1202 by wirelesscommunications. Signals are then processed by signal processing system114 to generate corresponding EOG signals (e.g. EOG waveforms 1210). EOGwaveforms 1210 are then analyzed by controller 112, other controllers inEOG system 1200, or external EOG system 1224 through the use of softwarealgorithms to determine the eye movement of the vehicle operator. In oneembodiment, when the EOG waveforms 1210 indicate that the individual isimpaired, such as by alcohol, drugs, tiredness and/or the like,controller 112 communicates with the vehicle's on board system, whichmay act in accordance with instructions from controller 112. In someembodiment, if the EOG waveform 1210 indicates that the vehicle operatoris going to fall asleep, is drowsy, or is already asleep, controller 112communicates an alarm instruction to the vehicle system, and the vehiclesystem, upon receiving the instruction, will sound an alarm insider thevehicle or increase the volume of the radio and/or music playing in theentertainment system to wake the vehicle operator. In some embodiments,the alarm may be a vibration of the operator's seat to wake the vehicleoperator. In further embodiments, the vehicle's infotainment system mayask the vehicle operator questions or require the vehicle operator toissue commands in order to wake or keep awake the vehicle operator. Inanother embodiment, if the EOG waveform 1210 indicates that the vehicleoperator is incapacitated, controller 112 will not permit the vehicle tostart or will communicate a stop instruction to the vehicle's system,and the vehicle's system will turn on the vehicle's emergency stoplights and slowly brake the vehicle to a stop. EOG system 1200 may alsocommunicate the vehicle operator's location and condition to emergencydispatchers such that emergency personnel can attend to the vehicle'svehicle operator quickly. Data from such vehicular EOG systems may berecorded—e.g. for forensic analysis, data analytics and/or the like. Insome embodiments, EOG system 1200 may be incorporated into militaryvehicles for use in adjusting weapon targeting systems and/ordetermining the state of the vehicle and/or weapon system operator. Insome embodiments, EOG system 1200 may interface or communicate withautonomous driving systems in a vehicle. In some embodiments, theautonomous driving system may take over operation of the vehicle wherethe EOG system 1200 indicates that the vehicle operator incapacitated orotherwise unable to operate the vehicle. In some embodiments, EOG system1200 may interface or communicate with a vehicle's safety systems, suchas active cruise control system, lane departure warning system, frontalcollision warning system, precrash system, collision mitigating system,collision avoidance system, and/or the like to reduce the likelihood ofan accident occurring while the vehicle operator is incapacitated orotherwise unable to operate the vehicle.

In one embodiment, a vehicle, such as a car, truck, bus, plane, train,ship, and the like, comprises ECG systems 100, 200, 300, 400, 900, EEGsystem 1000, EMG system 1100, or EOG systems 1200, or a combination ofall or some of the foregoing systems. The state of drowsiness of avehicle operator may be determined solely by ECG data (e.g. ECG waveform110), EEG data (e.g. EEG waveforms 1010), EMG data (e.g. EMG waveform1110), or EOG data (e.g. EOG waveform 1210) or a combination of all orsome of foregoing data. The use of sensors to provide ECG signals, EEGsignals, EMG signals, and EOG signals for determining drowsiness of avehicle operator is discussed in Sahayadhas, Arun et al., “DetectiveDriver Drowsiness Based on Sensors: A Review”, Sensors 2012, 12,16937-16953, and the content of the publication is hereby incorporatedby reference in its entirety. In these embodiments, ECG data, EEG data,EMG data, or EOG data may be generated from signals received byelectrode assemblies, and these electrode assemblies may comprisemulti-mode electrode units similar to multi-mode electrode units 600described herein. These multi-mode electrode units may operate incontact mode (current-sensing) or non-contact mode (current sensing orfield sensing), depending on the location or position of the vehicleoperator. In some embodiments, electrode units 600 comprise capacitivesensor element 606 and the capacitive sensor element 606 comprisesantenna component 652 and electrodynamic sensor 650 as described herein.In some embodiments, the same electrode assemblies are used to detectdifferent signals from the vehicle operator. In other embodiments,different electrode assemblies are used to detect signals from differentphysiological electrical activities of the vehicle operator (e.g.electrical activity of an organ, such as the heart (e.g. the heartmuscle), brain, eye, or skeletal and/or other muscle).

In one embodiment, ECG systems 100, 200, 300, 400, 900, EEG system 1000,EMG system 1100, or EOG systems 1200, or a combination of all or some ofthe foregoing systems, are used to monitor infants, babies, toddlers, oryoung children. Electrode assemblies, which may comprise multi-modeelectrode units similar to multi-mode electrode units 600 describedherein embedded within car seats, cribs, strollers, and/or the likeand/or in seat restraints, such as a seat belt, safety belt, and/or thelike, may detect electrical activity from different physiologicalelectrical activities ((e.g. electrical activity of an organ, such asthe heart (e.g. the heart muscle), brain, eye, or skeletal and/or othermuscle)) of the infants, babies, toddlers, or young children byoperating in current-sensing mode, field-sensing contact mode or fieldsensing non-contact mode (depending on the location or position of theinfant, baby, toddler, or young child). ECG data (e.g. ECG waveform110), EEG data (e.g. EEG waveforms 1010), EMG data (e.g. EMG waveform1110), or EOG data (e.g. EOG waveform 1210) may then be generated fromthe signals received by the electrode assemblies and analyzed asdescribed herein. ECG data, EEG data, EMG data, or EOG data may then betransmitted to a phone, tablet, computer, laptop, website, and/or thelike, and displayed to a parent, guardian, babysitter, teacher, and/orthe like to monitor the state of the infant, baby, toddler, or youngchild. In some embodiments, temperature sensor may also be added toprovide temperature information of the infant, baby, toddler, or youngchild with the ECG data, EEG data, EMG data, or EOG data or acombination of some or all such data.

While a number of exemplary aspects and embodiments have been discussedabove, those of skill in the art will recognize certain modifications,permutations, additions and sub-combinations thereof. For example:

-   -   In the illustrated embodiment of FIGS. 6A and 6B, cable 624 is        shown as being permanently attached to sensor portion 604. This        is not necessary. In some embodiments, cable 624 may be attached        to clamp portion 602 and the outputs of sensor portion 604 (e.g.        sensed signals) may be connected to cable 624 by suitable        electrical contact(s) between clamp portion 602 and sensor        portion 604. In some embodiments, connections to resistive        sensor elements (e.g. snap mechanism 622 and/or clamp contacts        636) can be routed through clamp portion 602 without the need        for sensor portion 602.    -   In some embodiments, clamp portion 602 of electrode unit 600 may        be fabricated from bacteria resistant material (e.g. suitable        plastic and/or the like).    -   In some embodiments, ECG systems 100, 200, 300, 400 may be        configured to provide a heart-shaped graphic on display 120 and        to interpret the ECG data to cause the heart-shaped graphic to        simulate actual heart-muscle activity as detected in the ECG        data.    -   In some embodiments, multi-mode electrode units 600 (or any        variations of multi-mode electrodes 600 described herein) may be        connected to prior art ECG, EEG, EMG, or EOG systems—e.g. in the        place of conventional electrode units. When connected in this        manner, suitable adapters may be used to provide output signals        from electrode units 600 in a format useable by the prior art        ECG, EEG, EMG, or EOG system.    -   In some embodiments, cables (e.g. cables 106, cables 624)        associated with the various electrode units or electrode        assemblies described herein may be retractable and may be        housed, for example, in the base unit or in the housing of the        electrode unit or electrode assemblies, as applicable.    -   In some embodiments, an electrode unit comprising a capacitive        sensor element 606 (see FIGS. 6A, 6B) could be incorporated into        a blood pressure cuff and attached to the body of an individual        via the blood pressure cuff to sense heart muscle electrical        activity in a field-sensing contact or field-sensing non-contact        mode.    -   In some embodiments, electrode units (e.g. electrode units 104)        and/or electrode assemblies (e.g. electrode assemblies 404) of        the type described herein may be used in non-contact        field-sensing mode for locating individuals (e.g. by their heart        activity or similar electrical activity) in a nonvisible        environment—e.g. as part of search and rescue operation in        rubble, avalanche, smoky rooms and/or the like. In some        embodiments, electrode units (e.g. electrode units 104) and/or        electrode assemblies (e.g. electrode assemblies) 404 of the type        described herein may be used in non-contact field-sensing mode        for motion detection systems. In some embodiments, electrode        units and/or electrode assemblies may be used at sporting events        or in public or private areas.    -   In some embodiments, electrode units (e.g. electrode units 104)        and/or electrode assemblies (e.g. electrode assemblies 404) of        the type described herein may comprise capacitive sensor        elements having an electrodynamic sensor sensitive to        electromagnetic waves and an antenna comprising an electrically        conducting radiating element for receiving electromagnetic waves        as described elsewhere herein.    -   Embodiments are described above wherein EEG system 1000 and EOG        system 1200 are implemented in a vehicle. In some embodiments,        any of the ECG systems described herein and/or EMG system 1100        may be implemented in a vehicular setting. Such embodiments may        comprise embedding electrode units and/or electrode assemblies        into components of the vehicle, such as (without limitation):        the steering wheel, the dashboard, the vehicle ceiling, the        vehicle floor, the vehicle seat(s), seat restraints, and/or the        like. Such ECG and EMG systems can be used to determine the        state of the heart muscle and/or the skeletal and/or other        muscle of the vehicle operator. Such information may be        communicated to first responders or suitable authorities in the        event of an accident or during normal vehicular operation        periods. Such embodiments can also alert the vehicle operator        (using suitable alarms and/or the like) that the vehicle        operator is having a heart attack or similar heart condition.        Data from such vehicular ECG systems and/or EMG systems may be        recorded—e.g. for forensic analysis, data analytics and/or the        like.    -   In some embodiments, a plurality of ECG systems 100, 200, 300,        400, 900, EEG systems 1000, EMG system 1100 and EOG systems 1200        may be implemented together in a vehicle for the purpose of        having redundant systems. Such systems may share a number of        common hardware components. The results from one system may be        used to confirm or augment the results from the other system.    -   ECG systems 100, 200, 300, 400, 900, EEG system 1000, EMG system        1100, and/or EOG systems 1200 may communicate ECG, EEG, EMG,        and/or EOG waveforms, as applicable, to a mobile device such as        a phone, tablet, and/or the like. In some embodiments, these        waveforms may be communicated to a website, cloud storage, or        other online databases.    -   Signals received by electrode units (e.g. electrode units 104)        and/or electrode assemblies (e.g. electrode assemblies 404) for        ECG systems such as ECG systems 100, 200, 300, 400, and 900 may        be analyzed to determine respiration patterns of an individual,        and the respiration information may be used alone or in        conjunction with ECG data (e.g. ECG waveforms) or other data        (such as EEG data, EMG data, or EOG data) to determine the state        of the individual, such as whether the individual is asleep,        drowsy, impaired, or is suffering from medical conditions    -   Signals received by electrode units and/or electrode assemblies        for ECG systems such as ECG systems 100, 200, 300, 400, 900, EEG        systems such as EEG system 1000, EMG systems such as EMG system        1100, and/or EOG systems such as EOG system 1200 may be analyzed        alone or in combination with other signals to determine the        medical state of an individual such as drowsiness,        unconsciousness, incapacity, brain injury, stroke, arrhythmias,        compensated shock, decompensated shock, sepsis, heart attack,        sleep, stress, attentiveness, cognition, respirations, internal        bleeding, and/or the like.    -   Software may be used to interpret ECG waveforms, EEG waveforms,        EMG waveforms, and/or EOG waveforms together to provide detailed        information about the state of an individual.    -   The electrode units (e.g. electrode units 104) and/or electrode        assemblies (e.g. electrode assemblies 404) of the type described        herein may be used to measure ECG, EEG, EMG, and/or EOG signals        based on instructions from software from the applicable system.    -   The electrode units (e.g. electrode units 104) and/or electrode        assemblies (e.g. electrode assemblies 404) of the type described        herein may also be incorporated or embedded into electronic        devices, such as phones, tablets, laptop computers, desktop        computers, smart watches, activity trackers, and the like,        and/or casing or other protective gear for such devices.    -   The systems and methods described herein are not limited to        humans and may be used for monitoring of animals, such as pet        animals or animals at zoos.    -   Display 120 of ECG systems 100, 200, 300, 400, 900, EEG systems        1000, EMG system 1100 and EOG systems 1200 may be the displays        of electronic devices, such as phones, tablets, laptop        computers, desktop computers, smart watches, and/or the like.    -   ECG systems 100, 200, 300, 400, 900, EEG systems 1000, EMG        system 1100 and EOG systems 1200 may be used for detection of        signals from individuals located in or travelling with public        areas, such as streets, malls, airports, ports, and/or the like.    -   Where the electrode units described herein capture signals        related to the operation of cell(s), tissue(s), organ(s) and/or        system(s), the controllers of the systems described herein may        be configured to use these signals (individually and/or        together) to create and display an animation on a suitable        display. The animation may be based on the one or more signals        and may show the operation of the cell(s), tissue(s), organ(s)        and/or system(s).    -   EMG systems described elsewhere herein are described in        connection with skeletal muscle. This is not necessary. In        general, the EMG systems described herein may be used in        connection with the electrical activity of other (non-skeletal)        muscles and/or a combination of skeletal and other muscles.

It is therefore intended that the scope of the following appended claimsand claims hereafter introduced should not be limited by the embodimentsset forth in the examples, but should be given the broadestinterpretation consistent with the description as a whole.

What is claimed is:
 1. A system for sensing physiological electricalactivity in an individual comprising: a first electrode unit forgenerating a first signal indicative of the physiological electricalactivity at a first location on a body of the individual; and a secondelectrode unit for generating a second signal indicative of thephysiological electrical activity at a second location on the body ofthe individual; wherein each of the first and second electrode units isconfigurable to operate in: a field-sensing mode wherein the electrodeunit is configured to generate its corresponding signal based on adetected electric field at a location on or in proximity to theindividual's skin; and, wherein each of the first and second electrodeunits comprises a capacitive sensor element, the capacitive sensorelement of each of the electrode units comprising: an electrodynamicsensor which is sensitive to electromagnetic waves; and an antennacomprising an electrically conductive radiating element for receivingelectromagnetic waves, the radiating element in electrical contact witha sensing surface of the electrodynamic sensor and having a surface areawhich is larger than a surface area of the sensing surface of theelectrodynamic sensor, the antenna located relatively more proximatethan the electrodynamic sensor to the individual's skin during operationof the electrode unit in the field-sensing mode.
 2. A system accordingto claim 1 wherein the physiological electrical activity compriseselectrical activity of an organ, the organ comprising a heart, a brain,an eye, or a skeletal muscle.
 3. A system according to claim 2 whereinthe organ comprises the heart and system is configured to combine thefirst and second signals to generate an ECG waveform.
 4. A systemaccording to claim 2 wherein the organ comprises the brain and thesystem is configured to combine the first and second signals to generatean EEG waveform.
 5. A system according to claim 2 wherein the organcomprises the eye and the system is configured to combine the first andsecond signals to generate an EOG waveform.
 6. A system according toclaim 2 wherein the organ comprises the skeletal muscle and the systemis configured to combine the first and second signals to generate an EMGwaveform.
 7. A system according to claim 1 wherein the capacitive sensorelement of each of the electrode units comprises an electricallynon-conductive layer disposed on the radiating element, wherein thenon-conductive layer is on an outside face of the electrode unit whichis located relatively more proximate than the radiating element to theindividual's skin during operation of the electrode unit in thefield-sensing mode.
 8. A system according to claim 7 wherein theelectrically non-conductive layer comprises a metallization layerelectrically connected to an inner metallization layer in directelectrical contact with the electrodynamic sensor.
 9. A system accordingto claim 8 comprising an insulator layer to provide a compressive forcefor facilitating the direct electrical contact.
 10. A system accordingto claim 1 comprising a distal component to provide electrical noiseshielding.
 11. A system according to claim 1 wherein at least one of theelectrode units comprises a clamp.
 12. A system according to claim 11wherein the clamp is provided in a clamp portion of the electrode unit,the capacitive sensor element is provided in a sensor portion of theelectrode unit and the clamp portion and sensor portion are attachableto, and detachable from, one another.
 13. A system according to claim 11wherein the clamp comprises a pair of clamp teeth for clamping objectstherebetween and the clamp is shaped to clamp the individual's clothingbetween the clamp teeth and to thereby affix the at least one electrodeunit to the individual's clothing.
 14. A system according to claim 11wherein the clamp comprises a pair of clamp teeth for clamping objectstherebetween and one or more electrically conducting clamp contactslocated in one or both of the teeth for clamping a portion of aresistive sensor element between the clamp teeth and correspondingelectrical attachment of the resistive sensor element to the one or moreclamp contacts, and wherein the at least one of the electrode units isconfigurable to operate in a current-sensing mode wherein the electrodeunit is configured to generate its corresponding signal based on currentflow through the resistive sensor element placed directly on theindividual's skin.
 15. A system according to claim 1 wherein at leastone of electrode units comprises a first connector component forreceiving a second complementary connector component of a resistivesensor element for removably electrically connecting the resistivesensor element to the electrode unit by connecting the first and secondconnector components, and wherein the at least one of the electrodeunits is configurable to operate in a current-sensing mode wherein theelectrode unit is configured to generate its corresponding signal basedon current flow through the resistive sensor element placed directly onthe individual's skin.
 16. A system according to claim 15 wherein thefirst and second connector components are shaped such that connectingthe first and second connector components causes deformation of at leastone of the first and second connector components and correspondingrestorative forces which tend to maintain the connection between thefirst and second connector components.
 17. A system according to claim 1wherein the capacitive sensor element of each electrode unit comprises afirst connector component for receiving a second complementary connectorcomponent of a resistive sensor element for removably electricallyconnecting the resistive sensor element to the electrode unit byconnecting the first and second connector components, the firstconnector component located on a side of the electrodynamic sensoropposite that of the antenna, and wherein the at least one of theelectrode units is configurable to operate in a current-sensing modewherein the electrode unit is configured to generate its correspondingsignal based on current flow through the resistive sensor element placeddirectly on the individual's skin.
 18. A system according to claim 1wherein at least one of the electrode units comprises a first sensorconfigured to detect a presence of a resistive sensor elementelectrically connected to the at least one of the electrode units.
 19. Asystem according to claim 18 wherein the at least one of the electrodeunits comprises a second sensor configured to detect proximity of theindividual's skin and to thereby permit determination of whether theelectrode unit is operating in a non-contact field-sensing mode whereinthe at least one of the electrode units is not in contact with theindividual's skin or a contact field-sensing mode wherein the at leastone of the electrode units is in contact with the individual's skin. 20.A system according to claim 1 wherein the first electrode unit isoperating in a non-contact field-sensing mode wherein the firstelectrode unit is not in contact with the individual's skinsimultaneously with the second electrode unit operating in a contactfield-sensing mode wherein the second electrode unit is in contact withthe individual's skin and wherein the system is configured to combinethe first signal and the second signal to generate a waveform.
 21. Asystem according to claim 1 wherein the system is configured to combinethe first signal and the second signal to generate one or more waveformsand to use the waveforms to determine a medical state of the individual.22. A system according to claim 1 wherein the second electrode isconfigurable to operate in a current sensing mode wherein the secondelectrode unit is configured to generate its corresponding signal basedon current flow through a resistive sensor element placed directly incontact with the individual's skin and wherein the first electrode unitis operating in the field-sensing mode simultaneously with the secondelectrode unit operating in the current-sensing mode and wherein thesystem is configured to combine the first signal and the second signalto generate a waveform.
 23. A system according to claim 1 comprising abase unit connected to the electrode units to is receive the first andsecond signals, the base unit comprising a digital signal processorconfigured to generate one or more waveforms based on a combination ofthe first and second signals.
 24. A system according to claim 23 whereinthe system is incorporated into a vehicle and at least one of theelectrode units and the base unit are located in the interior of thevehicle.
 25. A system according to claim 24 wherein the electrode unitis embedded into a seat in the vehicle and the base unit is incorporatedinto the head unit of the vehicle.
 26. A system according to claim 25wherein at least one of the electrode units is wirelessly connected tothe base unit.
 27. A system according to claim 23 wherein the base unitis configured to display the one or more waveforms on a display.
 28. Asystem according to claim 27 wherein at least one of the electrode unitsis incorporated into the steering control of the vehicle.
 29. A systemaccording to claim 23 wherein the system is configured to use thewaveforms to determine a medical state of an operator of the vehicle.30. A system according to claim 25 wherein the medical state isdrowsiness, unconsciousness, incapacity, brain injury, stroke,arrhythmias, compensated shock, decompensated shock, sepsis, heartattack, sleep, stress, attentiveness, cognition, respirations, orinternal bleeding.
 31. An electrode unit for use in sensingphysiological electrical activity in an electrical activity monitoringsystem, the electrode unit comprising: a capacitive sensor element fordetecting electric field, the capacitive sensor element comprising: anelectrodynamic sensor sensitive to electromagnetic waves; an antennacomprising an electrically conductive radiating element for receivingelectromagnetic waves, the radiating element in electrical contact witha sensing surface of the electrodynamic sensor and having a surface areawhich is larger than a surface area of the sensing surface of theelectrodynamic sensor, the antenna located relatively more proximatethan the electrodynamic sensor to the individual's skin during operationof the electrode unit a field-sensing mode.
 32. An electrode unitaccording to claim 31 comprising: a spring-biased clamp for attachmentof the electrode unit to an individual's clothing when operating in anon-contact field-sensing mode.
 33. An electrode unit according to claim31 comprising an attachment means for physical and electrical attachmentof the electrode unit to a resistive sensor element when operating in aresistive mode.
 34. An electrode unit according to claim 31 wherein theelectrical activity monitoring system comprises an ECG system, EEGsystem, EOG system, or EMG system.
 35. An electrode unit according toclaim 31 wherein the capacitive sensor element comprises an electricallynon-conductive layer disposed on the radiating element, wherein thenon-conductive layer is on an outside face of the electrode unit whichis located relatively more proximate than the radiating element to theindividual's skin during operation of the electrode unit in thefield-sensing mode.
 36. An electrode unit according to claim 35 whereinthe electrically non-conductive layer comprises a metallization layerelectrically connected to an inner metallization layer in directelectrical contact with the electrodynamic sensor.
 37. An electrode unitaccording to claim 36 comprising an insulator layer to providecompressive force and facilitate proper the direct electrical contactbetween the metallization layer and the inner metallization layer. 38.An electrode unit according to claim 31 comprising a distal component toprovide electrical noise shielding.
 39. An electrode unit according toclaim 33 wherein the attachment means comprises a first connectorcomponent for receiving a second complementary connector component ofthe resistive sensor element for physical and electrical attachment ofthe electrode unit to the resistive sensor element by connecting thefirst and second connector components.
 40. An electrode unit accordingto claim 34 wherein the first and second connector components are shapedsuch that connecting the first and second connector components causesdeformation of at least one of the first and second connector componentsand corresponding restorative forces which tend to maintain theconnection between the first and second connector components.
 41. Anelectrode unit according to claim 33 wherein the attachment meanscomprises a first connector component for receiving a secondcomplementary connector component of the resistive sensor element forphysical and electrical attachment of the electrode unit to theresistive sensor element by connecting the first and second connectorcomponents and wherein the first connector component is located on aside of the electrodynamic sensor opposite that of the antenna.
 42. Anelectrode unit according to claim 33 wherein the attachment meanscomprises the clamp, the clamp comprising a pair of clamp teethconfigured to hold a portion of a resistive sensor element therebetween.43. An electrode unit according to claim 32 wherein the clamp comprisesone or more electrically conducting clamp contacts located in one orboth of the teeth for providing electrical contact to the resistivesensor element.
 44. An electrode unit according to claim 31 wherein theelectrode unit is incorporated into a vehicle.
 45. An electrode unitaccording to claim 44 wherein the electrode unit is in wirelesscommunication with a head unit of the vehicle and communicatesinformation about the electric field to the head unit.
 46. An electrodeunit according to claim 31 wherein the electrode unit is incorporatedinto a seat or a steering control of the vehicle.
 47. A method forsensing physiological electrical activity of an individual comprising:providing a first electrode unit for generating a first signalindicative of the electrical activity at a first location on a body ofthe individual; providing a second electrode unit for generating asecond signal indicative of the electrical activity at a second locationon the body of the individual; operating the first electrode unit andsecond electrode unit in field-sensing mode to generate the first signaland the second signal; and using the first signal and the second signalto generate one or more waveforms indicative of the electrical activity,wherein each of the electrode units comprises a capacitive sensorelement, and the capacitive sensor element of each of the electrodeunits comprises: an electrodynamic sensor which is sensitive toelectromagnetic waves; and an antenna comprising an electricallyconductive radiating element for receiving electromagnetic waves, theradiating element in electrical contact with a sensing surface of theelectrodynamic sensor and having a surface area which is larger than asurface area of the sensing surface of the electrodynamic sensor, theantenna located relatively more proximate than the electrodynamic sensorto the individual's skin during operation of the electrode unit infield-sensing mode.